System for providing two-way communication and a central controller for use in a communication system

 

(57) Abstract:

The invention relates to messaging systems with parallel access code and seal channels (CDMA), in particular to vnutristranichnoy the messaging system in which a fixed base stations are organized in groups reusable sequences. The technical result - ensuring the detection of the base station transmitted signals with spread spectrum. System for providing two-way communication contains a base station (15) for transmission and reception of information and the Central controller (10), associated with the base stations (15) for controlling them. The Central controller (10) selectively assigns a seed for generating pseudo-random sequences of each of the base stations (15) in accordance with the information sent and received by base stations (15). 2 C. and 10 C.p. f-crystals, 20 ill.

The invention relates to messaging systems with parallel access code and seal channels (CDMA), in particular to vnutristranichnoy CDMA - based messaging system in which a fixed base stations are organized in groups of multiple use posledovatelnyi device Radiocommunication portable subscribers, and at least one stationary base station to transmit messages on the device Radiocommunication for subsequent presentation to subscribers. In some such systems, one or more radio communication devices can be made in the form of transceivers performing signal transmission and receiving messages from the base station. These systems are characterized as two-way messaging.

In systems, two-way transmission of messages, the portable transceiver may transmit signals to the base station in some cases. For example, the portable transceiver may transmit a signal to the base station to send a message to confirm receipt of the message or for display on the base station that the mobile transceiver is located in the coverage area of the base station.

In present systems, one-way transmission of messages, such as paging systems, in a typical case, the selected frequency channel, for example at a frequency of 25 kHz. To make this system as a two-way transmission of messages, handheld transceivers require limited bandwidth to the base station, e.g. is adachiku to use low levels of power during transmission. However, you must pass with a very low speed to balance vnutristranichnoy valve low power with high speed vagrancy channel high power. If the channel multiplexed vnutriserdechne low-speed signals, the set of portable transceivers can share a single channel.

A possible way of multiplexing group narrowband vnutrisemejnyh signal is concurrent access in systems with frequency division multiplexing (FDMA). However, FDMA with a narrow band of frequencies has the undesirable property that requires high precision local generators portable transceivers to save every signal within the spectrum allocated to it. In order to fully utilize the spectrum for FDMA, it is necessary to provide almost absolute accuracy of generating frequencies in portable transceivers that are associated with high costs. And, assuming the decrease of the accuracy of generating frequencies in the local generators of the transceivers is necessary to provide sufficient guard band between vnutriserdecnami the subchannels. However, this leads to inefficient and signals is the use of parallel access in systems with a code seal channels (CDMA). CDMA portable transceivers are simple to implement in comparison with portable transmitters used in narrowband FDMA systems, because the multiplexing occurs in the code domain, where frequency accuracy is not critical. In addition, the guard band between the subchannels are not required, since all subchannels occupy the same spectrum. However, it is well known that the limit for CDMA systems are interference, i.e., limited number of simultaneously transmitting portable transceivers. In addition, the existing CDMA systems are often characterized by the so-called problem of the middle-DXing. This problem occurs when the stationary base station cannot detect vnutristranichnoy signal spread spectrum, which is significantly lower power than other simultaneously vnutriserdechne signals with spread spectrum. Therefore, in order to ensure the proper operation of the CDMA system, it is necessary to control the amount of mutual interference in vnutristranichnoy the channel, which depends on the flow of information exchange. In addition, it is usually necessary to employ sophisticated power management, portable prempreeda is all transmitted signals with spread spectrum.

Thus, there is a need in the CDMA system, which would solve the problem of the middle-DXing and at the same time allow flexibility in relation to the number of simultaneously transmitting portable transceivers. In addition, it would be desirable to have a portable transceivers CDMA system did not require additional complex power management schemes or frequency.

According to the first aspect of this invention, in the communication system containing a base station for communication with the portable transceivers and a Central controller to control the operation of base stations and to determine the initial values (when generating pseudo-random sequences), the method includes the steps of identifying a Central controller which initial values are ready for use and assignment of available initial values of the first base stations.

According to the second aspect of this invention, the communication system to implement a two-way message transmission contains a base station for transmitting and receiving information and a Central controller associated with the base stations to operate them. The Central controller selectively imposed on the stations.

Fig. 1 is an illustration of a messaging system in accordance with the preferred embodiment of the present invention.

Fig. 2 - 9 - timing diagram depicting the Protocol signals messaging system shown in Fig. 1, in accordance with the preferred embodiment of the present invention.

Fig. 10 is a diagram illustrating the ordering of the groups re-use in the messaging system of Fig. 1 according to a preferred variant implementation of the present invention.

Fig. 11 is a block diagram of the Central controller, included in the messaging system of Fig. 1, in accordance with the preferred embodiment of the present invention.

Fig. 12 is a block diagram of an algorithm illustrating operation processing unit included in the Central controller of Fig. 11, in accordance with a preferred variant of the present invention.

Fig. 13 is a block diagram of a subscriber unit that is included in the messaging system of Fig. 1, in accordance with the preferred embodiment of the present invention.

Fig. 14 and 15 is a flowchart of an algorithm depicting operationcenter implementation of the present invention.

Fig. 16 is a block diagram of the algorithm depicting subsequent operations performed by the microcomputer included in the subscriber unit of Fig. 13, in accordance with the preferred embodiment of the present invention.

Fig. 17 is a block diagram of a base station included in the messaging system of Fig. 1, in accordance with the preferred embodiment of the present invention.

Fig. 18 is a block diagram schematic of suppression, included in the base station according to Fig. 17, in accordance with the preferred embodiment of the present invention.

Fig. 19 and 20 is a flowchart of an algorithm illustrating the process of compensation of mutual interference for a microcomputer included in the base station according to Fig. 16, in accordance with the preferred embodiment of the present invention.

According Fig. 1, the messaging system with concurrent access and code multiplexing of channels (CDMA), in accordance with the preferred embodiment of the present invention, contains the Central controller 10 to control multiple base stations 15, each of which has a coverage area within which it transmits radio frequency (RF) signal. Prov.Oh line, although, alternatively, the Central controller 10 can be connected to the base stations 15 through a telephone network or a radio frequency link. The messaging system also contains a variety of subscriber units (devices) 20, i.e., portable transceivers that accept information, including the selected call messages from the base stations 15. According to the present invention the subscriber's device 20 may also transmit information such as signals "confirm", vnutriserdechne messages, and so on, at the base station 15. The subscriber's device 20 preferably transmit the information to the base station 15 using the methods of spread spectrum communications, in which expansion of a signal in a given frequency band used pseudosolenia (PN) sequences or codes. Pseudosolenia sequence generated subscriber devices 20 and depend on the information transmitted to the subscriber's device 20 base stations 15. This information in General includes information about the bends defining the place of connection of the drain of the feedback, and the initial state of the shift registers, which can be used to generate pseudotumour posledovatelnyh numbers. In addition, the information includes information about the bit register that specifies the length of the initial numbers.

Messages can be transferred to the Central controller 10 to 25 phone through a telephone network such as a public switched telephone network (PSTN) 30 or private telephone station with access to a common network. Additionally, messages can be received by the Central controller 10 via the PSTN 30 from another device 35 input, such as a personal computer, a modem 40. Preferably, the identification information corresponding to each message received at the Central controller 10 at the time when the message is sent. For each message, the Central controller 10 compares the supplied identification information with addresses of subscriber devices stored in memory. Thereafter, the Central controller 10 reads the address associated with the subscriber device 20, which sent the message, and displays the address and message to the base station 15 having a coverage area in which it may be desired subscriber unit 20. Then the base station 15 decodes the address and message in the selective signal is ustrious format transfer Protocol signals, used in accordance with the preferred embodiment of the present invention. As shown in Fig. 2, the communication Protocol signal includes multiple frames, each of which includes a header, a consistent message and broadcast message, during which all the base stations 15, included in the messaging system, transmit at the same time. It is desirable that the transmission of serial communications are made with high data rate, in comparison with the circular transmission of the message. For example, the data transmitted in the serial transmission can be transmitted at a rate of 12 kilobytes per second (KBS), while the data transmitted during the circular transmission can be transmitted at a speed of 1200 KBS. In accordance with the present invention when the serial transmission of the base station 15 are alternately transfer, one at any given point in time in the direction of the Central controller 10, to allow each subscriber unit 20 to determine which base station 15 transmits the strongest signal. Preferably, the serial transmission for each base station 15 contained the word (code) synchronization (sync), variable infoadvantage transmission to the Central controller 10 gives a command to the first base station, the base station 1, at the beginning of the transmission. As shown in Fig. 2, the base station 1 transmits the word synchronization (sync), during which the subscriber unit 20 located within the zone of confident reception by the base station 1 are synchronized with the transfer. After that, the base station 1 transmits a variable containing the message field, and field initial numbers, and each field contains one or more initial numbers for use of subscriber devices 20.

Variable information is preferably accompanied by the transfer of persistent information, which is issued by the Central controller 10 for transmission to the subscriber's device 20 located in the coverage area of base station 1. In accordance with a preferred embodiment of the present invention, a constant information contains permanent information "starting word, the information bit register that specifies the length n of the initial number, and connection information of taps, each of which is stored subscriber devices 20 for subsequent initialization of the generator sequences located at each subscriber's device 20, as will be described in more detail n is arranged in the subscriber devices 20 in their manufacture. However, programming on channel allows you to modify, if necessary, using the Central controller 10 information about the bitness of the registers and how to connect the taps. For example, information about the bitness of the registers and how to connect the taps can be changed through programming on the channel that provides the subscriber device 20 move from one CDMA messaging system to another. In accordance with the present invention, the same information bit registers and how to connect the taps is transmitted to each of the base stations 15, included in the messaging system.

Constant information, in addition, contains clearly defined start number, different for each of the base stations 15 within the messaging system, in contrast to the information bit registers and connecting bends. The first numbers represent a binary number having n bits, where n is the length determined in accordance with the information of the bit registers.

Seed passed to each of the base stations 15, including base station 1, during the transfer constant of information include the initial values of podtverjdayuschie 20 method, described below. Initial values LAC and INIT preferably should be unique for each base station 15.

When entering into the messaging system, for example when switching on the subscriber's device 20, each incoming subscriber unit 20 waits for the reception of the header that declares the beginning of a frame of transmitted data. After this, the subscriber unit 20 ignores the variable information to be passed to each of these 15 stations during serial transmission, and receives permanent transfer of all of the base stations 15, with coverage that includes a subscriber unit 20. Subscriber unit 20 determines which of the transmitting base station 15 has the strongest signal and stores static information, i.e. information about the bit registers, the connection of taps and the initial values generated by this base station 15 for subsequent use, as will be described below.

When the incoming subscriber unit 20 remembered permanent information provided during the serial transmission of the base station 15 having the strongest signal, the subscriber unit 20 waits for the beginning of the next circular front is leucaemia in circular gear. In accordance with a preferred embodiment of the present invention at the beginning of the circular transmission to the Central controller 10 issues per base station 15 addresses of all subscriber devices 20, for which the Central controller 10 has received the message. Additionally, each base station 15, is included in the messaging system, simultaneously transmits during time bucket t0the sync word, which is different from the word synstraff transmitted during serial transmission. After the sync word followed by the addresses of each of the subscriber devices 20 that should receive messages, i.e., the address issued by the Central controller 10.

If, for example, in a messaging system included N subscriber devices 20 and M subscriber devices 20 received messages, each base station 15 transmits the address associated with each of the M subscriber devices 20. M subscriber devices 20 receive address and within a specified period of time passed-LACK, so that each subscriber unit 20, which has received the message may be in the messaging system. LACK transmitted to the base station 15, which was previously identified subscriber device 20 as keyset his address during the circular transmission, that means that the subscriber device 20 not expected to receive any messages, subscriber unit 20 preferably maintains persistent information transmitted by the base station 15 having the strongest signal during the next serial transfer, and again waits for his address during the circular transmission.

Since the subscriber unit 20 is responsible only base station 15, which adopted the strongest signal, all of the subscriber's device 20 which communicate with a particular base station 15, preferably located within a radius of reliable reception of the base station 15.

As mentioned above, each vnutristranichnoy message, each including LACK transmitted subscriber devices 20 to the base station 15, is passed as Segal spread spectrum, preferably at the center frequency of the allocated frequency bands. This extended spectrum signal generated using psevdochumoy sequence, i.e. a sequence of zeros and ones, to stretch the signal in the selected frequency band. According to the present invention pseudosolenia sequence generated by the generator posledovatelnostyakh as LACK, which determines the initial state of the shift register, and the information bit register that defines the length of the initial number, and information about connecting bends, which determines the connection of the drain of the feedback. All of this information allocated by the base station 15 having the strongest signal.

To transfer a given amount of data, i.e. the number of bits included in vnutriglaznogo message, the subscriber's device 20 requires a period of time Tscalled symbolic time, which depends on the bandwidth of the system and the length of the initial numbers, which determines the length of the sequences transmitted for each character. Character time Tsis defined by the formula

< / BR>
where n is the length of the initial numbers specified by the information bit registers, and BW is the bandwidth of the system. It is desirable that the length n of the initial number was set equal to seven, in order to obtain the desired win Ncduring processing, i.e. the number of elements per character for vnutrisemejnyh messages transmitted from the subscriber devices 20 on the base station 15. Win Ncwhen processing is determined by the formula Nc= 2N- 1.

sto which is transferred a certain amount of data (symbol), such as LACK, is approximately 10 MS.

Because LACK transmitted subscriber device 20, depending on the initial values LACK issued by the base station 15 that is defined as having the strongest signal, the target base station (destination station) 15 can recognize LACK transmitted subscriber's device 20. For example, if the subscriber unit 20 determines during the serial transmission of constant information that the base station 15 has the strongest signal, the subscriber unit 20 stores information about bit registers, connection information of taps and the initial number issued by the base station 15. After that, in a given time interval, which preferably has a duration of 10 MS, i.e., symbolic time subscriber unit 20 uses the information about the bit registers, connection information of taps and the initial value of the LACK issued by the base station 15, to generate and transmit its values LACK to the base station 15. As the other base station 15 expect LACK of reception, generated by using different initial and 15, even within the range of the subscriber's device 20, recognize that LACK is designed to receive another base station. Thus, each base station 15 is able to determine which subscriber units 20 are within its area coverage.

In addition, since the initial values, such as LACK and INIT are transmitted to the subscriber unit 20 base stations 15 during each frame, the subscriber's device 20 can conveniently relocate to another cell, i.e., to another base station 15 within the messaging system. After this, the subscriber unit 20 simply remembers the original number issued by the new base station 15, and resumes the connection using the initial number transmitted by the base station 15.

In accordance with a preferred embodiment of the present invention each of the subscriber devices 20 transmits its LACK in the time interval following the time interval of transmission of the address, by circular messages. In Fig. 4 shows the preferred format of the transmission of the k-th subscriber device that is associated with the address k. After achieving synchronization in a time interval of tthe time interval tk+1the k-th subscriber device sends LACK. LACK depends on the initial values LACK transferred to the base station, which was determined to be the k-th subscriber device with the serial transmission as having the largest signal. Therefore, in accordance with the present invention, the target base station 15 detects LACK and can determine the subscriber's device 20 has transmitted LACK.

Fig. 5 illustrates a situation in which the subscriber device M transmits LACK in the time interval tM+1. As described above, LACK generated by the subscriber device, M, depends on the initial values LACK transmitted by the base station 15, which was identified subscriber unit M sequential as having the strongest signal. During the time interval tM+1in which is passed a "zero" address, the destination station 15 receives from LACK subscriber unit M. then all the base stations 15 transmit "closure", which informs the subscriber's device 20, which is circular mode is finished.

As described above, the transmission of each message, i.e., symbol, such as a LACK, from subscriber device 20 requires approximately 10 MS, while the circular transmission base camp and devices 20, are 50-bit addresses, each address requires 41,67 MS for transmission from the base station 15. Therefore, if you are using a 50-bit addresses, each subscriber unit is capable of transmitting four repetitions LACK of duration 10 MS during transmission consecutive addresses in the next time interval. Errors result when the base station 15 "skips" LACK, decrease, because the energy of the re-transmitted LACK four times more than if the program was one time, providing better noise performance.

According Fig. 2, after completing the circular transmission to the base station 15 issues through specialized wire line to the Central controller 10 address of subscriber devices 20, which were accepted LACK. The Central controller 10 then assigns the appropriate number of clearly defined initial numbers of the base station 15 to pass as variable information. In addition, the Central controller 10 generates a message received via PSTN 30 (Fig. 1), to the base station 15, which is specified subscriber unit 20 passed LACK. As described above, the Central controller 10 may also, if necessary, to change the info is good to variable information transmitted from each base station 15, contained the seed issued by the Central controller 10, and after messages. The first numbers include the initial values of the confirmation message (MACK), which are subscriber devices 20 to confirm receipt of the message selective calling and the initial value data initialization (INIT DATA). Preferably, each base station 15 passed at least two initial values MACK each subscriber device 20, which should receive the message transmitted by the base station 15, and from which base station 15 took LACK during circular transmission. Upon receipt of a message included in the message field, as will be described below, the subscriber unit 20 uses the first initial value of the MACK for generating a first confirmation message (MACK) or the second initial value MACK for generating the second MACK, recognized by the base station 15 as different from the first MACK. The first MACK may, for example, to show that the subscriber unit 20 has received the message, while the second MACK can show the base station 15 that sent the message had too many errors and should Nochnoe the initial value of the MACK subscriber devices 20, who should receive the message. Transmission MACK, formed using the initial values MACK can then show that the message was accepted, and, conversely, the absence of a response from the subscriber's device 20 may indicate that the message should be retransmitted.

If, for example, the base station 1 receives from LACK of two subscriber devices 20, such as subscriber device and the terminal device b, the base station 1 generates the addresses of the two subscriber devices 20 to the Central controller 10. Then the Central controller 10 displays a message intended for reception by each of the two subscriber devices 20, to the base station 1. Optional initial values MACK issued to the base station 1 for each of the two subscriber devices 20 that should receive the message. If subscriber units a and b should receive messages and LACK issued to the base station 1, it is desirable that the Central controller 10 were given four clearly defined initial values MACK, each of which has a bit depth n, to the base station 1 after the completion of the circular gear. During transmission of the variable information, the base station 1 transmits the address a, which is associated with s as the initial value MACK, referred to as MACKa,1. Then, similarly to the base station 1 simultaneously transmits the address of b, followed by the initial values MACKb,0and MACKb,1. In this way, each of the subscriber devices 20 that transmitted LACK to the base station 1 receives two initial values MACK, which it must respond to the message included in the subsequent field of the message.

As described above, the serial transmission is transmitted to the base stations 15 when the data transfer speed of 12 KTS, which is ten times higher than the speed of data transmission as a broadcast transmission. Therefore, if the messaging system uses a 50-bit addresses, each address will be transmitted to the base stations 15 approximately 4,2 MS. However, like LACK, MACK requires transmission time in 10 MS (for n = 7 and BW = 25 kHz). In the MACK preferably not transmitted until such time as the base station 15 will not complete the transfer field of messages that can be understood from Fig. 6, 7 and 8.

In Fig. 6 shows an example of the format field of the message to the base station 15, for example, the base station 1. In accordance with the present invention, all the base station 15 in the messaging system uses the same format during Pereda devices a and b is shown as receiving messages from the base station 1, which first sends the address a, followed by a message intended for the receiving subscriber device a, and completion (closure), indicating that the subscriber device a, that the message transmission is completed. After that, the base station 1 transmits the address of b, followed by a message intended for the receiving subscriber device b, and a trailer. In accordance with the present invention, then the base station 1 transmits the final trailer for specifying user devices a and b that the transfer of the message field is completed.

In an alternative embodiment of the present invention, the initial values MACK specific subscriber device 20 could occur immediately after the fields MACK (Fig. 2). In this alternative embodiment, subscriber unit 20 should take the address and then save the initial values MACK, issued by the base station 15. After that, the message should be accepted subscriber device 20, which should generate MACK, as described below.

In Fig. 7 and 8 shows the responses, i.e., MACK passed subscriber devices a and b in accordance with the preferred embodiment of this izaberete is B> or MACKa,1. Message MACK formed with the MACKa,0that may mean that the message is received without errors. On the contrary, the message MACK formed with the MACKa,1may specify that a message should be retransmitted at a later time. Similarly, the subscriber device b transmits the proper MACK, generated by using MACKb,0or MACKb,1. In accordance with a preferred variant of the present invention, messages MACK sent to subscriber devices a and b after transmission of the final trailer, the base station 1 at the beginning of the subsequent time frame duration of 10 MS. Alternative messages MACK can be transmitted to each subscriber device 20 immediately upon receipt of a message, i.e., during the next available time frame duration of 10 MS. The base station 1 is able to distinguish the two response because the messages MACK generated using different initial values MACK, issued by the base station 1.

If after sending the message, the base station 15 does not accept MACK from the target subscriber unit 20, the base station 15 may re-transmit the message for the subscriber device is not handed MACK. In response, the Central controller 10 may store the message until such time as the target subscriber unit 20 will not send again LACK to one of the base stations 15.

In accordance with a preferred embodiment of the present invention the subscriber's device 20 may also initiate communication with the base station 15. As described above, each base station 15 transmits during a serial transfer is uniquely defined initial value INIT. The subscriber's device 20 retains the initial value INIT, transferred to the base station 15, which was identified as having the strongest signal during the previous serial transmission. After that, if the subscriber's device 20 to initiate communication with the base station 15, which gave the stored initial value INIT, the subscriber generates by using the initial value INIT connection information of taps and a bit registers, the signal INIT to transmit to the base station during any time interval of duration 10 MS. In response to the signal INIT base station 15 marks signal INIT value real-time specifies the time interval, when it was adopted whitefish is x base station 15 received signals INIT. These initial values INIT DATA transmitted in the INIT field DATA, which preferably follows the field that is allocated to the initial values MACK and which is also included in the variable information.

In accordance with the present invention, each subscriber device 20, which previously gave the signal INIT to the base station 15, highlights L the initial values INIT DATA, where L is an integer, preferably defined by the expression L = 2j, j is a positive integer. Therefore, if one of the L vnutrisemejnyh messages should be transmitted to the subscriber device 20 within the symbolic time of the order of 10 MS, the number of bits that can be included in the symbol time Tsis given by the expression Nbits= log2L. Then we can see that when the number of initial values INIT DATA assigned to the subscriber device 20 increases, the amount of information included in the character time Tsalso increases. Thus, when the number of initial values INIT DATA assigned to the subscriber device 20 increases, vnutristranichnoy message having a fixed length, i.e., vnutristranichnoy message containing a fixed number of bits that can be transmitted to the subscriber device in response to the subscriber's device 20.

By the way, which can be accomplished by assigning initial values INIT DATA is the appointment by the Central controller 10 all initial values INIT DATA base station 15, which currently transmits variable information in which at least one subscriber unit 20 sends a signal to INIT, as can be better understood by referring to Fig. 9.

In Fig. 9 presents a diagram illustrating the transmission field INIT DATA base station 15, such as a base station 11, which previously received signals INIT from K subscriber devices 20, where K is equal to or greater than one. Preferably, the base station 15 been in communication over a wired line with the Central controller 10 before sending INIT field DATA, for example during transmission fields MACK, to inform the Central controller 10 on the number of subscriber devices 20, which previously gave the signal INIT to the base station 15. Then the Central controller 10 determines which of the initial values INIT DATA are available, and assigns the available initial values INIT DATA base station 15. Then, the base station divides the available initial values INIT DATA evenly between K subscriber devices 20 for transmission in the INIT field DATA. M the properties 20, the Central controller 10 does not need to issue the initial value INIT DATA to the base station 15 and base station 15 do not need to pass the initial value INIT DATA to any subscriber unit 20.

In accordance with a preferred variant of the present invention, if the subscriber's device 20 gave the signal INIT to the base station 15, the base station 15 transmits the initial value INIT DATA at the subscriber unit 20 in the order in which the base station 15 received signals INIT from subscriber device 20. However, instead of passing addresses to identify subscriber devices 20, the base station 15 transmits values corresponding to time intervals that have been taken by the signal INIT, because the addresses of the subscriber devices is unknown. Therefore, each of the subscriber devices 20, which previously gave the signal INIT to the base station 15 will be transferred to recognize the value of the time interval and to remember the corresponding initial value INIT DATA.

Accordingly, the first base station 15 will pass, in the INIT field DATA, the time interval of the first received signal INIT, i.e., the time interval 1. Subscriber unit 20, which sent the signal INIT for lying INIT DATA. After that, the base station 15 transmits a certain number of initial values INIT DATA for receiving subscriber device 20, which passed the signal INIT during time interval 1. As mentioned above, this number of initial values INIT DATA preferably equal to the number of available initial values INIT DATA divided by K subscriber devices 20, which previously sent the signal INIT to the base station 15. Since the number of initial values INIT DATA issued by the terminal device 20 may vary, the base station 15 additionally transmits the trailer after passing the initial values INIT DATA for each subscriber unit 20 to show that the transfer of the initial values INIT DATA given subscriber device 20 is completed.

For example, if three of the subscriber's device 20 has transmitted the signal INIT to the base station 15, and the Central controller 10 has issued twenty-four existing initial value INIT DATA to the base station 15, each subscriber unit 20 will take eight initial values INIT DATA from the base station 15 during the INIT field DATA. As a result, each of the three subscriber devices 20 will be able to send three bits of data to the base station 15 during character time that predp subscriber devices 20 will take four initial values INIT DATA and will be able to send two bits of data in each symbol time. It is therefore desirable to produce as much as possible initial values INIT DATA to the subscriber's device 20, which will be transmitted vnutriserdechne messages.

Preferably, the subscriber's device 20 has started transmission vnutrisemejnyh message to the base station 15 as soon as the initial values INIT DATA will be taken from the base station 15. Each vnutristranichnoy message is followed in accordance with the preferred embodiment of the present invention pointer "end of messages", in response to which the base station notifies the Central controller 10 that the initial value INIT DATA used by the subscriber device 20 for transmission vnutriglaznogo messages, the more they are used.

However, a situation may arise when the base station 15, the leading serial transmission may request a large number of initial values INIT DATA before they will be available from the Central controller 10. This can for example happen if the base station 15, the leading serial transmission, will ask for the initial value INIT DATA before any of the subscriber devices 20, which have been allocated all the available initial values INIT DATA, completes sweet to give only part of the available initial values INIT DATA to the requesting base station 15 and keep the rest in reserve and not to give each possible initial value INIT DATA to the requesting station 15. So back to the initial value INIT DATA can be transmitted to the base station 15, the leading serial transmission, in situations where all of the subscriber's device 20 previously received initial values INIT DATA, even passed vnutriserdechne messages.

In accordance with a preferred embodiment of the present invention, the subscriber unit 20 during character time is able to transmit only a certain number of bits included in vnutristranichnoy message, where the number of bits is determined by the number L of initial values INIT DATA assigned to the subscriber's device 20. These bits are defined by the equation Nbits= log2L, is transmitted in the form of a signal spread spectrum direct sequence, preferably at the center frequency of the selected frequency band. However, in an alternative embodiment of the present invention the subscriber's device 20 may transmit more than one frequency. For example, when using two frequency offset such as +/- 500 Hz, the subscriber's device 20 may send one of two signals with spread spectrum on price is inoe time. In the more General case, when using any number of frequencies, instead of one Central frequency, number of bits per symbol time is determined by the equation Nbits= log2(NfL),

where Nf- a positive integer representing the number of possible frequencies at which the subscriber's device 20 may transmit.

Alternatively, data may be transmitted in the form of various pseudotumour sequences on the same frequency or in the form pseudotumour sequences at different frequencies. These cases represented by formulas

Nbits= Nf(log2L) and

Nbits= L(log2Nf)

respectively.

Although in accordance with the preferred embodiment of the present invention the subscriber's device 20 is able to initiate communication with the base stations 15, obvious other alternative embodiments of the present invention, in which the subscriber unit 20 simply able to give confirmation of the location and messages (and LACK MACK) to the base station 15. In such alternative embodiments, the base stations 15 do not need to pass the initial value INIT, members of permanent info is a row of base stations 15 in the messaging system. As shown, the messaging system contains many cells grouped in clusters. Shows the seven cells in the cluster that reflects one of the various examples of the types of clusters that are known to a person skilled in the art. Each cell includes a predetermined communication area, which is one base station 15, and a similar number of cells located at a fixed distance from all other similarly numbered cells. The distance between cells is determined by the cluster size and the radii of the cells.

In accordance with a preferred embodiment of the present invention the base station 15 are grouped into seven (7) of the seven (7) groups of reuse, and the base station 15 within each group reuse denoted by Roman numerals I-VII. Subscripts to Roman numerals indicate the group number. For example, the fifth base station in a fifth group, designated as V5. If the transmit power of each subscriber unit 20 is adjusted correctly, then the initial value (LACK, MACK, INIT and INIT DATA) transferred some of the base stations 15, can be re-used by other base stations 15 in the system parentsa device 20, associated with the base station 1 in each group can re-use the same initial values. With this method, if the base station 15 in the first group reuse requests an initial value INIT DATA, for example, from the Central controller 10, when all the initial values INIT DATA is not available, the Central controller 10 can determine whether any of the initial values INIT DATAN at this time, the base station 15 of the same rooms in the other group reuse. If so, these initial values INIT DATA can be appointees and therefore reused requesting the base station 15, which provides an advantage in the possibility of increasing the number of subscriber devices 20 that can be transmitted in a single time interval.

In Fig. 11 presents a block diagram of the Central controller 10, made in accordance with the preferred embodiment of the present invention, intended to control the operation of base station 15 (Fig. 1) included in the CDMA transmission system messages. The Central controller preferably includes a telephone interface 105 for connecting the PSTN 30 (Fig. 1) to block obrabotkami 20, from the PSTN 30. In addition, the Central controller 10 contains a lot of data ports 110, connected to the processing unit 108 to transmit and receive data from the base stations 15, preferably through a dedicated wire line. Watch 111, connected to the processing unit 108, produce the actual time used by the processing unit 108 to generate signals for running gear as circular, and consequently, from the base stations 15.

When the call is answered, the processing unit 108 performs processing of the message. The processing unit 108 preferably is a microcomputer, such as MS or equivalent, manufactured by Motorola Inc., he performs various pre-defined program management operations of such a Central controller, such as verbal cues, prompting a caller to enter messages and other Alternative, the processing unit 108 may be performed using the rigid logic circuits capable of performing the required processing functions.

After receiving the message, the processing unit 108 stores the message in the buffer 112 messages and accesses the information stored in the database 115 subscribers to determine how seesa, assigned to the subscriber device 20 included in the messaging system, the message type associated with the address and information associated with the status of the subscriber's device 20, for example, active or inactive from the point of view of payment. Provides a terminal 120 of the input, which is connected to the processing unit 108 and which is used for purposes such as enter, update, and erase the information stored in the database 115 subscribers, to control the operation of the system and to obtain information such as account information.

With the processing unit 108, in addition, linked database 125 initial numbers, which houses many of the initial numbers. Preferably, the base 125 data entry numbers included at least one start value and LACK INIT in the messaging system. Or, if the messaging system is formed group reuse, as shown in Fig. 10, the database 125 initial

values might include at least one start value and LACK INIT for each base station 15 in the group reuse. Therefore, using a finite number of initial values in the messaging system more archlinux values further includes the initial values MACK and INIT DATA for use of subscriber devices 20, included in the messaging system.

As described above, the processing unit 108 generates signals that are transmitted through the data ports 110, determining in each base station 15 a beginning and an end gear in a circular and sequential modes. At the beginning of each circular transmission frame processing unit 108 reads the address of any subscriber devices 20, for which messages stored in the buffer 112 messages. Then, the processing unit 108 transmits the address and the enable signal of the circular mode through the ports 110 data at the base station 15. After that, the base station 15 perform circular transfer addresses and take from LACK of existing subscriber devices 20, i.e., from receiving food, properly functioning and located in the area of the base stations 15. At the end of the circular transmission of each base station 15 transmits to the Central controller 10 address of subscriber devices 20, from which were obtained from LACK, in response to which the processing unit 108 reads the messages from the buffer 112 messages for transmission to the appropriate base station 15. In addition, the processing unit 108 preferably assigns the corresponding base station 15, at least two initial values of M is determined as being the embodiment of the present invention, each base station 15 before passing his INIT field DATA associated with the Central controller 10, to request an initial value INIT DATA if one or more subscriber devices 20 gave the signal INIT to the base station 15. This relationship, which is preferably different times for each base station 15 transmits information on the number of subscriber devices 20, from which the base station 15 has received the signal INIT. In response to receiving the request, the initial values of the processing unit 108 accesses the database 125 data initial values INIT DATA. It is desirable, if only not been allocated a certain part of the initial values INIT DATA as a backup to any existing initial value INIT DATA were issued to the requesting base station 15 for transmission to the subscriber device 20, which sent signals to INIT to the requesting base station 20. Thus, during the time when only a small number of subscriber devices 20 initiated the connection, the greater number of initial values INIT DATA may be issued to each of the subscriber devices 20. Therefore, the subscriber's device 20 can transmit more data to the base station 15 in one time interval of the symbol. It can be noted that the selection of initial values INIT DATA provided for the way in which vnutriserdecna transport the topic. Accordingly, when the system load is low, i.e., when only a small number of subscriber devices 20 has transmitted signals to INIT, this subscriber devices 20 appoint a larger number of initial values INIT DATA, and they, therefore, can transfer data faster.

This process is easier to understand, referring to Fig. 12, which presents a block diagram of an algorithm illustrating the process by which the processing unit 108 of the Central controller 10 can assign initial values INIT DATA base stations 15. In accordance with a preferred embodiment of the present invention, the processing unit 108 receives at step 140 request initial values from one of the data ports 110. Request initial values is passed to the data port 110 from the requesting base station and includes information, which can be determined the number of subscriber devices 20, requesting the connection. After that, at step 145, the processing unit 108 accesses the database 125 data initial values (Fig. 11) to identify the initial values that are currently not assigned to any base stations 15 in the messaging system. When in the messaging system, there are groups to re-use the values of any relevant base stations 15, included in various group reuse. After that, the processing unit 108 at step 155 determines the number of available initial values. If reuse is not used in the messaging system, the number of available initial values simply equal to the number of unassigned initial values. Alternatively, when there are re-used, the number of available initial values corresponds to the number of initial values assigned to the respective base stations 15 in different groups of reuse, the same applies to the number of unassigned initial values.

If, at this moment ready to use initial values are not available, then at step 160, the processing unit 108 may generate a signal of failure of initial values for transmission at step 165 to the requesting base station through the data port 110. If, on the other hand, it is determined that the initial values are available, the processing unit 108 reads at step 170 a subset of the available initial values from the database 125 data initial values. As described above, this subset may include each possible initial value, or if the Central controller 10 of theprogrammer the s values without this part. In both situations, a subset of the available initial values is served at the stage 180 in the data port 110 for transmission to the requesting base station for use as initial values INIT DATA. After that, at step 185, the processing unit 108 preferably marked in the database 115 data subscribers each subset of the available initial values to indicate that they are assigned to the base station 15. Then, when any initial values are no longer used by the subscriber device 20 for transmission to the requesting base station requesting the base station sends a signal to indicate that this initial value is no longer used. In response to the reception signal processing unit 108 marks is the initial value, thus indicating that she again refers to unassigned.

As mentioned above, ready-to-use initial value INIT DATA may also include, if the messaging system is included reusable group, the initial value INIT DATA, the currently assigned base station 15 in the other group reuse with the same number of base stations that the requesting base station 15. For example, the base station 1 can nd in other groups re-use in the messaging system. Preferably, the initial value for MACK and INIT DATA included in the variable information, again marked as "available" (available), when the Central controller 10 is notified of the base stations 15 that subscriber units 20 do not need to use the initial values.

In Fig. 13 presents a block diagram of the subscriber unit 20 in accordance with a preferred embodiment of the present invention. Subscriber unit 20 includes an antenna 200 for transmitting and receiving radio frequency (RF) signals and the switch 205 connecting the antenna 200 to the receiver 210 and transmitter 215. It is desirable that the switch 205 default mode "reception", in which the signals are received by the antenna 200 and issued to the receiver 210 to receive the signal "transfer", in response to which the switch 205 transmits the signal generated by the transmitter 215.

As is well known to a person skilled in the technical field, the receiver 210 demodulates adopted the RF signal to select data from it. In addition, according to the present invention, the receiver 210 contains the indicator of received signal level (RSSI) 220 for determining the level of a received signal. The results of esmeria/output (1/0). In accordance with a preferred embodiment of the present invention demodulated data is processed by the Central processor unit (CPU) 235 inside the microcomputer 225 to decode addresses, values of time intervals, messages, initial values and data included in the permanent information transmitted by the base stations 15 (Fig. 1). The decrypted information is then stored in a storage device, random access (NVR) 240.

In addition to the NVR 240 microcomputer 225 contains a permanent memory (ROM) 245, such as an electrically erasable programmable ROM (EEPROM), which stores the routines that control the operation of the subscriber's device 20. Additionally, the microcomputer 225 includes the generator 250 to generate the signals used in the operation of the microcomputer 225. Crystal oscillator 255 is connected to the generator 250 for issuing a reference signal for synchronization of the microcomputer 225. The counter 260, internal to the microcomputer 225 and connected to a generator 250 generates a programmable timing function used in the control of the microcomputer 225.

In accordance with predpochtitelen to the microcomputer 225 through the 1/0 bus 230. Generator 265 pseudotumour sequence preferably is a shift register that, when providing information about the position of the taps and the initial number of length n generates pseudotumour sequence of length 2n- 1. Information about the position of the taps may, for example, include information, which can be installed a lot of programmable switches in the shift register. As mentioned above, the length n of the initial number preferably equal to seven to get proper processing circuit for transmitted signals. Therefore, the generator 265 pseudotumour sequences generates pseudosolenia sequence, having a length of 127 elementary time intervals, when the length of the initial number is equal to seven.

In response to receiving the message intended for the subscriber unit 20, the Central processing unit 235 outputs a signal for triggering the generator 270, which allows the pathogen 275 Converter provide power to the transducer 280. The Converter 280 is switched on and off by receiving the reference signal generator 250, with the frequency depending on the programmed value of the frequency, granade generates during the time interval, programmable memory codes 285, audible warning to alert the user about the reception of the message. After that, the user can choose to view the message by manipulating driven by user agencies 290 control (adjustment) connected to the microcomputer 225 through the 1/0 bus 230. In response to user-initiated signal from regulators 290 Central processing unit 235 reads the message on the NVR 240 for subsequent transfer to the pathogen 295 display, which is part of the microcomputer 225. Pathogen 295 supplies the display 300, and transmits the message on the display 300 for subsequent presentation.

In Fig. 14 and 15 presents a flowchart of the algorithms, explaining the operation of the microcomputer 225 (Fig. 13), when the subscriber unit 20 is energized. In accordance with a preferred variant of the present invention, the Central processing unit 235 (Fig. 13) ignores all of the information included in the received radio-frequency (RF) signals to the receiving stage 310 header indicating the start of the frame. Thereafter, the Central processing unit 235 reaches the synchronization status at step 315 to the base station 15, the leading serial transmission. Same 320 receiving the starting words of the permanent information then the Central processing unit 235 stores the measurement results of the signal levels generated by the level indicator 220 (Fig. 13), and permanent information transmitted by the base station 15, at stages 322, 325 in NVR 240. In accordance with a preferred variant of the present invention, a constant information contains information about the bit register that specifies the length n of the initial value and the information about the bends, which is used by the microcomputer 225 to start the generator 265 pseudotumour sequences. Constant information also contains the initial values and LACK INIT, as mentioned above.

After memorizing a signal level and a constant information from the Central processing unit 235 determines whether completed serial transmission constant information, trying to find at stage 330 of the word synchronization (SOPS) circular transmission. If at step 330 the word synstraff circular transmission is not detected, the Central processing unit 235 performs synchronization with the subsequent base station 15 and controls the level of the transmission signal to determine at step 335, a higher level of subsequent transmission of the base station 15 than filled value urovnya subsequent base station 15 is replaced by the steps 322, 325 previously saved in NVR 240 permanent information and the signal strength value. This process continues until, until it finds the word sync circular transmission, at this point, the microcomputer 225 will remember the constant information transmitted by the base station 15, from which the received transmission with the highest level. Preferably, the subscriber unit 20 at this point was located at a distance from the base station 15, is comparable with the distances to other subscriber devices 20, corresponding to the same base station 15.

Once detected in step 330 words sync circular transmission to the Central processing unit 235 receives the circular gear. During this transfer, the Central processing unit 235 accept addresses and determines at step 336 whether the address associated with the subscriber device 20. If this address is detected at step 336, which means that the message for the subscriber unit 20 will be sent, then at step 340 the initial value and LACK information about connecting bends and bit registers are read from the NVR 250 is fed to the generator 265 pseudotumour sequences (Fig. 13). After that, the generator 265 generates and outputs pseudotumour posledovateley on stage 350 pseudotumour sequence at the transmitter 215 (Fig. 13) and at step 352 generates the signal "transfer" to activate the switch 205 and the enable signal LACK with extended range to the base station 15 during the 10 MS time interval with duration of 10 MS. Because LACK is generated using the initial values LACK issued by the base station 15, the base station 15 recognizes the LACK as a pointer that the subscriber unit 20 is located in the coverage area of the base station 15.

After that, at step 355, the Central processing unit 235 is again synchronized with the base station 15 for serial transmission to receive the initial values of the confirmation message (MACK) transmitted in the field of MACK the base station 15. If at step 360 Central processing unit 235 detects the address corresponding to the subscriber's device 20, the two initial values MACK accompanying address, remember to step 365 NVR 240. Specialist in the art, however, it is obvious that in alternative embodiments implementing the present invention on the subscriber's device 20 may be filed either larger or smaller, of the two initial values. Thereafter, the Central processing unit 235 expect the dres subscriber unit Central processing unit 235 determines at step 375 the status of the message. Status messages, such as accept or non-deductable, can be determined through the implementation of the detection algorithm and error correction, as it is known to specialists in this field of technology.

If at step 375, the message is determined to be accepted, it is stored and processed as described in Fig. 13. Additionally, at step 385, the Central processing unit 235 selects the first of the two initial values MACK, which is recognized by the base station 15 as signaling accept message. If, on the contrary, the message of non-deductable, then at step 390, the Central processing unit 235 selects the second initial value of the MACK, which may indicate, for example, that the message must be retransmitted by the base station 15. The selected initial value of the MACK together with information about the bitness of the registers and how to connect the taps is fed to step 395 to the generator 265 pseudotumour sequences (Fig. 13), which then generates and sends to the stage 400 pseudotumour sequence to the Central processing unit 235, passing it on stage 405 to the transmitter 215, which generates a signal corresponding to the MACK extended range. The MACK signal is transmitted to the subscriber Stroyservice 10 MS after the end of the trailer, transferred to the base station 15 to indicate the end of message field. It can be noted that the time interval of 10 MS may change depending on changes in bandwidth and gain for the signal processing, as described above.

After taking MACK the base station 15 may determine that made whether the message is in accepted state or not, by deciphering psevdochumoy sequence to determine which of the two initial values MACK was used to generate psevdochumoy sequence. If, in accordance with the preferred embodiment of the present invention the base station 15 determines that the message was in non-deductable status, address of the subscriber's device 20 through a dedicated wire line is transmitted to the Central controller 10 (Fig. 1). Preferably, the Central controller 10 kept the message up until the subscriber unit 20 will not transmit again LACK to the base station 15, is included in the messaging system. After this message you can give to another base station 15 for re-transmission to the subscriber's device 20.

It is shown in Fig. 16 block diagram of the algorithm is illustrated . the accordance with the preferred embodiment of the present invention, the subscriber unit 20 is able to initiate communication and to transmit vnutriserdechne messages to the base station 15. Communication can be initiated, for example, or in response to manipulation by the user handles adjust 290 (Fig. 13), or automatically, for example, at a particular time of day.

As shown in the description of a system, subscriber unit 20 receives and stores permanent information, such as information about the bitness of the registers, how to connect the taps, the initial LACK and INIT issued by the base station 15 with the highest level of signal during serial transmission. Then, if should be initiated communication with the base station 15, the Central processing unit 235 reads the initial value INIT and information about the registers and how to connect the taps of the NVR 240 for transmission at step 420 on the generator 265 pseudotumour sequences (Fig. 13). In response, the generator 265 generates pseudotumour sequence of maximal length, which is supplied to step 425 to the Central processing unit 235, which provides on-stage 430 pseudotumour sequence at the transmitter 215 for Codorniu unit 235 at step 435 generates the signal "transmission", managing the switch 205 to connect the transmitter with the antenna 215 205 during the time interval x.

As described above, the base station 15 receives the signal initiating the connection (INIT) and stores the value of the time corresponding to the time interval of x in memory. Then before passing INIT field DATA included in the variable information, the base station 15 communicates with the Central controller 10 to inform the Central controller 10 on the number of received signals INIT, in response to the Central controller 10 outputs to the base station 15 is ready for use initial values, denoted as the initial value INIT DATA. These initial values INIT DATA transmitted by the base station 15 during the INIT field DATA.

Once the signal INIT Central processing unit 235 synchronized at step 440 to the base station 15 during serial transmission. If at step 445, the value of the time corresponding to the time interval of x passed to the base station 15 and detected by the Central processor unit 235, the initial values INIT DATA following the time value memorized at step 450 in NVR 240. However, the specialist in the art it is clear that there is a possibility that the x values INIT DATA, for example, when the subscriber's device 20 leaves the zone of confident reception by the base station 15. Therefore, it may be necessary in some circumstances to the Central processing unit 235 resumed work described in Fig. 14 and 15, for the reception of the corresponding initial value INIT to initiate communication with another base station 15.

As described above, the Central controller 10 assigns all existing (available) initial value INIT DATA or part of the base station 15 to distribute among any of the subscriber devices 20, from which the received signals INIT. Therefore, the number of initial values INIT DATA issued by the base station 15 each subscriber device 20, may vary. In the base station 15 additionally transmits the trailer after the appointment of the initial values INIT DATA to each subscriber terminal 20. The Central processing unit 235 receives at step 455 this trailer, and recognizes it as indicating that the transfer of the initial values INIT DATA to the subscriber's device 20 is completed.

After this, the subscriber unit 20 starts the transfer process vnutriglaznogo message to the base station 15. Vnutristranichnoy message the user selects through manipulation of the controls 290. Additionally, if the adjustment controls 290 include, for example, alphanumeric keypad, the user can generate the data included in vnutristranichnoy message by printing the characters on the keyboard. Preferably, the preset messages or generated by the user data is converted into binary data by a method well known to a person skilled in the technical field, which presents the initial values INIT DATA.

After storing the initial values INIT DATA Central processing unit 235 reads from NVR 240 and passes to step 460 in the generator 265 pseudotumour sequence information bit registers on connecting the taps and the selected initial value INIT DATA. The selected initial value INIT DATA is binary data included in vnutristranichnoy message. After that, the generator 265 generates a phase 465 pseudotumour sequence to the Central processing unit 235 for transmission at step 470 on the transmitter 215. After connecting on stage 475 switch 205 transmitter 215 to the antenna 200, the signal is spread spectrum, i.e., the signal is distributed in a selected frequency band using psevdochumoy a sequence of character time interval, for example, 10 MS. If vnutristranichnoy message that includes the word the end of the message, not completed at step 480, the Central processing unit 235 again selects at step 460 corresponding to the initial value INIT DATA and generating and sending pseudotumour sequences are repeated until until all bits of the data included in vnutristranichnoy message will not be transmitted to the base station 15.

As described above, when the signals are spread spectrum transmitted by the subscriber device 20, are formed on the same Central frequency, the number of bits that can be transmitted during character time (one character), i.e., 10 MS, preferably defined by the expression

Nbits= log2L,

where L is the number of initial values INIT DATA transmitted to the subscriber's device 20. Therefore, when the number of initial values INIT DATA transmitted to the subscriber's device 20 increases, the time interval in which the message is sent, is reduced.

For example, consider the situation when vnutristranichnoy message transmitted to the base station 15, contains the binary sequence data 101111001000". If your device is set eight R>
The initial value is the Number of

1 - 000

2 - 001

3 - 010

4 - 011

5 - 100

6 - 101

7 - 110

8 of 111

The initial value of 6 (101), which represents the first three bits in vnutristranichnoy the message can be used to generate the first psevdochumoy sequence that can be transmitted during one symbol. Similarly, the initial values of 8 (111), 2 (001) and 1 (000) may be used for subsequent generation of sequentially transmitted pseudotumour sequences, each of which should take a symbolic time for transmission. The result is a full vnutristranichnoy message can be transmitted within four character intervals of time, in accordance with the preferred embodiment of the present invention is approximately 40 MS.

However, if the subscriber's device 20 assigned only four initial values INIT DATA, the transmission time of the same message will be much more. Four initial values INIT DATA may, for example, to introduce the following 2-bit binary numbers:

The initial value is the Number of

1 - 00

2 - 01

3 - 10

4 - 11

In this case, the same message programming pseudotumour sequences for transmission to the base station 15. As you can see, the transfer vnutriglaznogo message in this case should require six character intervals of time or 60 MS. It can be noted, therefore, that it is beneficial to assign as much as possible initial values INIT DATA to each subscriber device 20, which must be passed vnutristranichnoy message.

As mentioned above, vnutristranichnoy message sent by each subscriber device 20, preferably includes the word the end of the message, which is detected by the base station 15 and is recognized as indicating that the transfer vnutriglaznogo message is completed. In response to the reception of the word of the end of the message from the subscriber unit 20, the base station 15 informs the Central controller 10 that the initial value INIT DATA assigned to the subscriber device 20, the latter is no longer used. After that, in accordance with the preferred embodiment of the present invention, the Central controller 10 may issue the initial value INIT DATA on request to other base stations. Alternatively, if you use a group reuse, the initial value INIT DATA can conveniently be used by other cells again and the 20 capable of receiving the initial value INIT DATA via radio, they can accept and use a different number of initial values INIT DATA to change the data rate to the base station 15. Therefore, the intensity of transmission vnutrisemejnyh messages, you can increase or decrease, depending on the system load, without including the subscriber unit additional or more complex synchronization schemes.

As shown in Fig. 17, the base station 15, in accordance with the preferred embodiment of the present invention, includes a receiving antenna 500 for receiving radio frequency (RF) signal and circuit 510 frequency conversion, connected to the receiving antenna 500, to convert the RF signal with decreasing frequency to the base band frequency to be processed by the method, which will be discussed below. The base station 15, also included the transmitting antenna 512 to transmit RF signals generated by the transmitter 515, subscriber units 20 located in the coverage area of the base station 15.

In accordance with a preferred embodiment of the present invention, the circuit 510 frequency conversion outputs a signal of a base band frequency to analog Converter 518 for deserveth digital signal, which is stored in buffer 520 signals. The digital signal is then processed, as will be described below, a controller, such as a digital signal processor 525, which is connected to the buffer 520 bus signals water/output (1/0) 530.

In addition, to the digital processor 525 using the 1/0 bus 530 is connected to the port 535 data, through which the base station 15 receives information from the Central controller 10 (Fig. 1), transmit to him the information. Preferably, as shown in the description of the system to the base station 15 was adopted before sending constant data (Fig. 2) information on the bitness of the registers, how to connect the taps and the initial values and LACK INIT from the Central controller 10 through the port 535 data. This constant information is fed into a Central processing unit 540, which is part of the digital signal processor 525, the Central processing unit 540 stores permanent information in NVR 545 connected to the block 540. In accordance with the present invention, the Central processing unit 540 also receives through port 535 data and stores the address of the subscriber devices, messages intended for reception by subscriber devices 20 (Fig. 1), and initial values MACK and INIT DATA, the 550, for example EEPROM, which stores the subroutines that control the base station 15. In addition, the digital signal processor 525 is enabled generator 555 to generate the signals used by the processor 525. Quartz generator 560 is connected to the generator 555 for forming a reference signal for synchronization in the processor 525. Counter 565, internal to the digital signal processor 525 and connected to a generator 555 generates a programmable timing function used in the control of the processor 525.

In accordance with a preferred embodiment of the present invention the generator 570 pseudotumour sequences associated with the digital signal processor 525 1/0 bus 530. The Central processing unit 540 generates an information bit registers, how to connect the taps and the initial value on the generator 570 pseudotumour sequences to generate possible pseudotumour sequences, with which the subscriber's device 20 can transmit signals with extended range to the base station 15. All possible pseudosolenia sequences can be saved in NVR 545 or alternatives is such a sequence can be completed and thereafter may be moved by means of a Central processing unit 540 to generate other possible pseudotumour sequences. These sequences are used by the digital signal processor 525 to decode the received signals with spread spectrum method, which is described below.

Specialist in the art it is clear that the size of the cells included in the messaging system may be such that pseudosolenia sequence will experience delays on one or more elementary time intervals. The maximum delay of the elementary time interval is approximated by the formula

,

where r is the cell radius in meters, BW - bandwidth RF signal with spread spectrum, c is the speed of light (3 of 108meters per second). For example, if the cell radius is 24 km, pseudosolenia sequence will have a delay from subscriber device 20 to the base station 15 in one elementary time interval. Therefore, it is possible pseudosolenia sequence used by the digital signal processor 525 to decode a received RF signal may include not only the sequence generated by the generator 570, but also formed pseudosolenia sequence shifted in time to account for delays at the elementary time interval. Literally, the digital signal itself may be shifted before processing in the digital signal processor 25. If, on the other hand, both these alternatives are undesirable, the cell size can be easily adjusted to eliminate delays at the elementary time intervals completely, providing less complexity physically smaller base station 15, which will have a smaller coverage area.

In accordance with a preferred embodiment of the present invention, the digital signal processor 525 includes a scheme 575 determine the power and frequency and a compensation circuit 580 used for decoding spread spectrum, as can be better understood by means of Fig. 18, which presents a block diagram of a compensation scheme 580. The compensation circuit 580 includes a first mixer 600 to compress the signal contained in the digital signal stored in the buffer 520 signals (Fig. 16). The compressed signal is applied to the circuit 575 determine the power and frequency to determine the peak spectral power of the Central frequency of the compressed signal. The compensation circuit 580, in addition, contains a band-pass filter 605, which is connected with the first mixer 600 for filtering the compressed signal to SF is rasshireniya filtered signals. In addition, the compensation circuit 580 is enabled, the adder 615 for subtracting the re-expanded signals from the digital signal stored in the buffer 520 signals. The compensation process can be better understood by means of Fig. 19 and 20.

In Fig. 19 and 20 shows the flowchart of the algorithm corresponding to the compensation process performed by the digital signal processor 525 (Fig. 17) in accordance with a preferred variant of the present invention. At the beginning of the character time interval, such as every 10 MS, the Central processing unit 540 sets at step 700, the value q of the counter is equal to (1), i.e. q = 1. Additionally, at step 702, the Central processing unit 540 stores in NVR 545 initial power value, which is set to zero, and the initial value of the frequency, which is set at the center frequency of the bandwidth, i.e., P0= 0 and F0= Fc. Then, at steps 705 and 710 Central processing unit reads the digital signal from the buffer 520 signals (Fig. 17) and q-th pseudotumour sequence on the NVR 545. The digital signal and the q-I pseudosolenia sequence serves to step 715 to the first mixer (Fig. 18), which at stage 720 performs signal compression by AA is 575 determine the power and frequency to determine at step 730 peak spectral power Pqand the center frequency Fqthe compressed signal. If at step 730 it is determined that the peak spectral power more than the initial power value filled in NVR 545, the Central processing unit 540 sets at step 735 the amount of power at the peak spectral power, and the initial value of the frequency at the center frequency of the compressed signal, i.e., P0= Pqand F0= Fq. In addition, at step 740, the Central processing unit 540 marks q-th pseudotumour sequence in NVR 545 for later identification.

Next, the Central processing unit 540 determines at step 745 the value is q, the number N of possible pseudotumour sequences that subscriber unit 20 could be used in signal transmission. As described above, depending on the size of the cells included in the messaging system, it is possible pseudosolenia sequence may include shifted pseudosolenia sequence or shifted digital signal to account for different delays at the elementary time intervals. As shown, this step 745 also occurs, if at step 730 peak spectral output compressed signata q will get an increment at step 750 the counter 565 (Fig. 17). Then at step 710 the following q-I pseudosolenia sequence is read from the NVR 545 and served on the stage 715 on the first mixer 600. The processes of compression, determine the power and frequency (steps 710 - 750) are repeated a digital signal processor 525 as long as the value of q will be equal to the number of possible pseudotumour sequence (q = N), which means that the peak spectral power and the Central frequency of all the compressed signals are defined. At this point pseudosolenia sequence corresponding to the compressed signal having the greatest spectral power, marked in the NVR 545, and the values of power and frequency compressed signal having the greatest spectral power stored in the NVR 545.

If at step 745 determined that q is equal to the number of possible pseudotumour sequence, the Central processing unit 540 at step 755 computes the value of the threshold power, based on the value of off-peak spectral power of the digital signal. If at step 760 it is determined that the peak spectral power of the compressed signal is less than the threshold power value, the Central processing unit 540 at step 765 waits for the next character time interval and again the local processing unit 540 may continue attempts to decode the signal by reference to the maximum capacity although a low level of signal power can lead to inaccurate data recovery.

If at step 760 it is determined that the peak spectral power of the compressed signal is greater than a threshold power, the Central processing unit 540 at step 770 determines that the compressed signal is received correctly and can be processed further. For example, if the peak spectral power of the compressed signal is greater than a threshold power, the Central processing unit 540 may determine the type and, if applicable, is psevdochumoy sequence, is used to compress the signal. Pseudosolenia sequence may, for example, correspond to the first initial value MACK, which was used by the subscriber unit 20 to indicate that the message was received correctly. In this situation, the base station 15 may notify the Central controller 10 that the message was accepted by the intending subscriber device 20 and may be removed from the buffer 112 (Fig. 11) the Central controller. Alternatively, pseudosolenia sequence may correspond to the initial value INIT; in this case, the Central processing unit 540 stores the time interval signal is accordance with the present invention, the compressed signal is applied to the bandpass filter 605 (Fig. 18), which filters the phase 775 compressed signal to form an estimate of the carrier frequency. After that, the estimation of the carrier frequency is mixed in the second mixer 610 with psevdochumoy sequence, was used to compress the signal, which leads to the re-expansion of the spectrum of the signal, which is subtracted at step 785 of the digital signal, filled in the buffer 520 signals. The resulting modified digital signal, i.e., the digital signal minus re-extended signal, replaces the digital signal in the buffer 520 signals. Additionally, the Central processing unit 540 removes at step 795 pseudotumour sequence from a list of possible sequences, filled in NVR 545. The compensation process, as described above, continues, or until, while on stage 800 there will be no possible pseudotumour sequences, or until, while on stage 760 peak spectral power of the strongest of the compressed signal becomes less than the threshold power value.

Thus, the base station 15 has the opportunity to decode all the signals received from the subscriber devices 20 in the coverage area of the base station 15. In addition, fortress, i.e., the strongest signal first, weaker signals can be suppressed more strong signals, it is easier detected base station 15. Therefore, the base station 15, in accordance with the preferred embodiment of the present invention greatly simplifies the problem of the middle-DXing present in many conventional CDMA communication systems, in which the weaker signals may be indistinguishable from the noise of the system.

In accordance with a preferred embodiment of the present invention the base station 15 determines the strongest signal, which is subtracted from the digital signal, then the process is repeated to determine the next strongest signal, followed by subtraction. This process is periodically repeated, as described above, up until the base station will not receive all the signals present in the digital signal. Since the strongest signal is removed at each iteration of the compensation process, this method ensures that each signal as accurately as possible. However, alternative embodiments of the present invention, in which the compensation process performed is estline base station 15 can identify not only the strongest signal, and a group of strong signals, and then the whole group is subtracted. As in the method described above, the process should be repeated until such time as all signals will not be decoded by the base station 15. This method can reduce the number of repetitions of steps required in the preferred embodiment. However, being more effective, the compensation process in accordance with an alternative embodiment of the present invention may be more inaccurate than described with reference to Fig. 19 and 20, where the strongest signals and thereby interference from stronger signals are removed one after the other.

Eventually CDMA transmission system with a narrow band of frequencies in accordance with a preferred embodiment of the present invention provides two-way communication between the fixed base stations and portable subscriber units in the system. Preferably, the Central controller connected to each base station managed by the base stations and distributed initial values of the base stations for onward transmission to the subscriber device. This distribution of initial values is performed in two different ways.

To fit the data initial values for transmission to the subscriber device. After that, each subscriber unit uses the initial values given by one of the base stations, for generating pseudotumour sequences for transmission to the base station in the form of signals with spread spectrum. The base station receives and decodes the signals spread spectrum transmitted during each selected time interval for recovery of the contained pseudotumour sequences. By using the method of compensating the base station has an opportunity to detect each PN sequence, which was generated using the initial values previously transferred to the base station.

Unlike conventional base stations base station according to the present invention before decoding each signal for recovery of the PN sequence determines the power level of each signal. After this, the signals are interpreted in the order determined by their level. Therefore, as the most powerful signals with spread spectrum compensated signal with the spread spectrum in the first place, the weak signals that cannot be detected in conventional systems, legkominsky device is able to simultaneously transmit to the base station. When applying the above described method need not be included in the subscriber unit complex control circuit power.

In accordance with the aspect of "vnutristranichnoy messaging" system base stations allocate initial values depending on the system load. If, for example, the base station receives from the subscriber devices a large number of signals initiating communication, the number of initial values to be issued to subscriber units, less than if the base station would be accepted by only a small number of signals initiating communication. Therefore, the number of initial values assigned to the subscriber device varies depending on the number of user devices requesting initial values of initiating communication. In the bandwidth of subscriber devices is changed, allowing the individual subscriber's device to send data faster during periods of time when the system has a smaller workload. Alternatively, when the system load is high, then a larger number of subscriber devices is capable of, but it requires a longer time for data transfer. In addition, this change of propusk the case of conventional CDMA systems.

Additionally CDMA system in accordance with the preferred embodiment of the present invention enables easy reuse of sequences in the system. Therefore, when certain cells of the system uses a set of sequences, the sequences can be reused in other designated cells. As a result, since the used sequences can be reallocated to other cells, the number of subscriber devices that can transfer in a given time interval, increases substantially.

From the above it follows that the proposed CDMA messaging system in which the bandwidth vnutrisemejnyh subscriber devices may change dynamically depending on the load of the system to increase or decrease the time during which a given amount of data can be transmitted to the subscriber device. In addition, this CDMA system is not experiencing the impact of the problems of the middle-DXing inherent in conventional CDMA systems and the resulting increase in the number of users within the system. In addition, the CDMA system in accordance with the preferred option Oswestry not contain more complex schemes.

1. Central controller for the distribution of the initial number of pseudo random sequences for use generators pseudo-random noise (PN) in the communication system with multiple access, code-division multiplexing (MDCRC) and with an extended range that contains a base station for communication with the portable transceivers, which include generators PSH, many of the initial number of pseudo-random sequences used for expansion and contraction signals with spread spectrum containing a processing unit and a storage device used to store the database of the subscriber, which is connected with the processing unit, characterized in that what storage device is additionally employed for storing the initial numbers in the database entry numbers, and in that it includes a data port for transmitting and receiving information from the base station, and a processing unit connected to the data port is activated for the initial distribution of the numbers of base stations in accordance with the information transmitted and received by the data port.

2. The Central controller under item 1, characterized in that the processing unit provides the marking of each and the th, transmitted and received by the data port.

3. The Central controller under item 2, wherein the processing unit generates the initial number of database entry numbers that are marked as unassigned, port data transfer with him and in response, marks the starting number as assigned.

4. The Central controller under item 3, characterized in that the processing unit additionally determines whether the assigned starting number for transmission from the data port.

5. The Central controller under item 2, characterized in that it further comprises a telephone interface connected to the processing unit for receiving messages, selective calling, and the processing unit distributes the seed stored in the database entry numbers, in response to receiving messages selective calling.

6. The Central controller under item 5, characterized in that it further comprises a message buffer, coupled to the telephone interface for temporary storage of messages to selective call received by the telephone interface.

7. The Central controller under item 6, wherein the processing unit generates a number of available initial colostomy initial numbers proportional to the number of messages to selective call stored in the message buffer.

8. The Central controller under item 7, characterized in that the number of available initial numbers issued from the database entry numbers, includes one or more of the initial numbers that were marked in the storage device as assigned.

9. Communication system with multiple access, code-division multiplexing (MDCRC) and spread spectrum to provide two-way communication containing a base station for transmitting and receiving information, characterized in that it contains a Central controller connected to the base stations and manages, with the Central controller has a storage device, in which many of the initial number of pseudo random sequences stored in the database of initial values, set the initial number of pseudo-random sequences used by generators of pseudorandom noise (PN) for generating PN sequences for expansion and contraction signals, and provides selective assignment of the initial numbers of each of the base stations in accordance with the information transmitted and received by base stations.

10. The communication system under item 9, characterized Tesla, passed at least one base station on the Central controller and the Central controller in response to it determines what the initial numbers stored in the database entry numbers are available, and generates at least one base station of the subset of available initial numbers.

11. The communication system according to p. 10, characterized in that it further contains at least one portable transceiver to transmit a signal initiating communication of at least one base station and at least one base station transmits a subset of the available initial number of at least one portable transceiver in response to receiving a signal initiating communication.

12. The communication system according to p. 11, characterized in that the Central controller in response to the submission of at least one base station of the subset of the available initial numbers from the database entry numbers marks each from a subset of the available initial numbers as unavailable, and at least one base station, if the initial number of the subset of the available initial numbers no longer used portable transceiver that transmits to the Central controller C the range is the initial number as available.

 

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