Random access in a mobile communication system

 

The invention relates to mobile communication random access, in which the mobile station transmits the first packet including a certain predetermined combination of signatures, in parallel with the second package, comprising part of the data request on the random access. Therefore, in addition to its inherent advantages of the part with the signature of the request for random access can also serve as the pilot signal by providing additional energy for channel estimation during the transfer of part of the data request at the same time reducing the number of existing above-ground signaling, which is a technical result. This extra energy is particularly useful for ensuring sufficient high-quality coherent detection part with the data in the rapidly changing environment of the radio channel. 3 C. and 10 C.p. f-crystals, 9 Il.

Cross references to related applications This patent application claims the use of priority and thus reference includes a complete description of simultaneously considering the provisional patent application U.S. 60/063024, filed October 23, 1997

This proposal object of the invention is to bid, medium, small

Background of the invention the technical Field to which the invention relates the Present invention in General relates to the field of mobile communications and, in particular, to a method of processing multiple calls to random access originating from a mobile subscriber.

Description of prior art There is a need in the next generation mobile communication systems to provide a wide range of communication services, including digital transmission of voice, video and data in packet and circuit switching fashion channels. The result is a significant increase in the number of calls that will lead to much higher density of traffic on the channels random access (cap). Unfortunately, this increased density of traffic will also result in increased collisions of requests and denials of access. Therefore, the new generation of mobile communication systems must use a much more robust and flexible procedure random access to increase their speeds and successful access and reduce the time of processing access requests.

In most mobile communication systems, such as for example, the European joint development, called the stupas to the base station by first defining readiness efficiency for use. Then the mobile station transmits the number of the header of the request for access (for example, individual characters of the chip 1023) with increasing power levels until such time as the base station does not detect a request for access. In response, the base station starts the control process is transferred to the mobile station power through the descending channel. As soon as it is finished the initial "handshake" between the mobile station and the base station, the user of the mobile station (subscriber) sends a random access message.

In the system SS-SRMA (Spread Spectrum Slot Reservation Multiple Access) technology is used kotirovalnogo random access S-ALOHA. At the beginning of the slot (time interval), the mobile station will send a packet random access to the base station and then wait for an acknowledgement of its receipt of the package. This technology S-ALOHA complete without a set of operations that characterize the CODIT system and the system is working on the standard IS-95 (namely, the linear change of power and control power).

More specifically, based on the CODIT system multiple access code division (CDMA) mobile station will attempt to access the base station receiver by using the process of "linearly knogo character. As soon as it detects the header of the request for access, the base station activates the control circuit power with a closed feedback loop that controls transmitted by the mobile station power level to maintain the desired level of power received from the mobile station signal. Then the mobile station transmits the specific data request access. The base station receiver "narrows" accept signals (extended range), using a consistent filter and combines the separation narrowed signals in order to use antenna diversity.

In the is-95 CDMA uses the same technology random access. However, the main difference between the CODIT based system CDMA, and is-95 CDMA is that the mobile station standard IS-95 transmits not only the title, and the full package random access. If the base station does not acknowledge receipt of the request for access, the mobile station re-transmits the packet random access at a higher power level. This process continues until the base station acknowledges the receipt of the request for access.

In the mobile communication system using the 01 (hereinafter referred to as "the'501 application"), the mobile station generates and transmits the packet random access. In Fig.1 shows a diagram which illustrates the structure of the data block for such a package. Package random-access ("data block of the access-request contains a header and a data field. The header contains a unique combination of signature (bits), which has a length "L" characters. The combination of signatures is randomly selected from a number of combinations that are orthogonal to each in relation to each other, but not necessarily. The mere use of this unique combination, as described and claimed in the '501 application, provides significantly higher throughput compared to previously known technology random access.

As described in the '501 application, the data field of the packet random access includes certain information random access, comprising information identifying the user of the mobile station, the number of the required services (services must be numbered), the required "air time" (time required for message transmission), the transmission of a short packet of data to improve transfer efficiency) and the excessive error detection (cyclic redundancy code). For reasons analyzed in detail in the '501 application, BA is different. However, one can imagine situations in which this condition is not required.

Package random access (such as shown in Fig.1) is transmitted by the mobile station at the beginning of the next available frame. In Fig. 2 shows a block diagram of a device that can be used in the mobile station to generate and transmit the packet random access, is illustrated in Fig.1. Essentially, as shown in Fig.2, the header and the data field of the packet random access are created and expanded separately (using the appropriate codes of the extension) and then compressed and transmitted to the mobile station.

Then, the packet random access is received and demodulated by the target base station using the receiver with the approved filter. In Fig.3 shows a block diagram of the detecting section (for one antenna) receiver random access base station, which serves mainly to assess synchronization rays of the received signal. Consistent filter, which is used only during the header period, is configured to code the header extension. Consistent filter is used to detect the presence of a query on arbitrary delaetsa unique tool, used for the method for random access, described in the '501 application, serves to sum the signals at the output of the matched filter for the header (M) symbol periods to increase the power ratio of the received signal to noise (s/n). As each accept header contains a unique combination of signatures, the summation operation is performed through a set of adders (1-l), each of which is configured to one of the possible received signatures.

In Fig.4 shows a simple block diagram of the adder, which can be used for the first channel (quadrature detection) in the detection section random access shown in Fig. 3. Similarly, the adder can be used for the quadrature channel. As shown in Fig.3 and 4, the output of each adder (signature 1-l) connected to the unit peak detection. At the end of the header period, each unit of peak detection searches the output signal of its corresponding matched filter for each peak of the signal that exceeds a predefined detection threshold. Then each block peak detection registers (finds and remembers) the magnitude and relative phase of kadodwala in the receiver. By itself, the synchronization of each peak is measured and used to establish parameters "Rake" (Rake) (sections 1-l receiver Rail). In Fig.5 shows a block diagram of the demodulator random access, which can be used for demodulation part with a data field of the packet random access. Essentially, the demodulator random access decodes information about the data in the received data field and checks for transmission errors.

Although described above with reference to Fig.1-5 device and method for random access have numerous advantages in comparison with previously known technology random access, there are still a number of problems to be solved. For example, it may be a large number of collisions of packets, if the mobile station in all cells use the same codes expansion during phases of the transfer of title or processing of the data field. The result should be transmitted to a large number of requests for random access, which can lead to system instability. In addition, when using the above device and method of the random access receiver with a consistent filter base station is not used as effectively as he can the MSC idle full period of time, the next stage of reception of the header. In addition, since the length of the packet random access used with the above-described technology is fixed, the size of the short data packets is limited by the extent of use of the remaining parts of the package. Because of all these reasons for solving these problems required the development of more flexible procedures request for random access.

In the above-mentioned patent application U.S. 08/847655 (hereinafter referred to as "the'655 application") described the successful solution of these problems. In accordance with the invention described and claimed in the '655 application, in the way each sector cell assigns a unique ID header extension and also unique long code, which binds to the short code extension data field (associated with the signature). The period of time selected for the long code can be relatively large in length (for example, to have a duration of hours to days). Therefore, we can say that the data field of the packet random access transmitted on the channel, as two messages can have the same extension sequence and phase (as long as they don't choose the same signature and will not give their tag the width of the time intervals of transmission, equal length header (minus practical reasons specified guard time interval). Therefore, the request for random access of the mobile station can be synchronized to start at the beginning of the time interval, and discovered during the header period of time through a matched filter receiver random access to the base station. The data field of the request on the random access of the mobile station is transmitted at time intervals following time intervals header, and accepted by the Rake receiver at the base station. However, in accordance with this method, after the header of the period of time agreed the filter is able to take the headers of requests for random access from other mobile stations. Therefore, consistent filter can be used continuously and efficiently, and can handle a significantly larger number of requests for random access in comparison with previously known technology random access. Itself bandwidth communications and the effectiveness of the system random access, using this method is significantly higher than the bandwidth of problemy random access, which must be solved. For example, in Fig.6 shows a diagram illustrating the structure of a channel packet random access (the format of the message sent over a common physical rising channel), which is formatted in accordance with the structures of the data block random access described above. Compared to previously known approaches, the format of the channel shown in Fig. 6, advantageously reduces the number of collision queries on random access, which can happen, and also simplifies the detection part with a data field of the packet random access. However, the drawback of using this format is that it is not directed at minimizing the number of existing above-ground alarms.

In Fig.6 shows that, in order to coherently detect the part with a data field of the packet random access, transferred a certain amount of energy in the form of a known modulated symbols (marked as "pilot signal"). The pilot signal may have a temporary seal, I/Q seal code seal with the data (indeed, the type of modulation is not essential for this discussion). General "overhead" energy package random agile can be used with the same purpose, as the pilot signal, assuming that the receiver makes the right decision on the signature transmitted in the header. Consequently, it would be possible to achieve a relatively good estimate of the signal within the header part of the request for random access.

However, in a rapidly changing radio channel the energy used for channel estimation, ideally should be expanded over time to exceed the data fields to achieve a sufficient quality of the assessment for this part of the request for random access. Even if you could achieve a sufficient quality of the channel estimation for the transmission header (due to excellent signature in the header) in a rapidly changing channel, this assessment would be incorrect for a significant part of the data request for random access. In itself, it is important to provide sufficient energy in the header for the receiver to detect the header and the correct identification of paths of the channel.

On the other hand, in a rapidly changing channel, it is also important to provide sufficient power in a pilot signal to guarantee the corresponding coherent detection part with the data. Unfortunately, these two important but contradictory energy blunt with excessive overhead signaling. In other words, the ratio of "overhead" energy (energy of the header plus the energy of the pilot signal) and the energy of the "data" is too high with its attendant disadvantages. However, as described in detail below, the present invention successfully solves these problems.

Summary of the invention In accordance with a preferred embodiment of the present invention provides a new format General physical upstream channel in a mobile communication system with random access, thus the mobile station transmits the first packet comprising a predetermined combination of signatures, in parallel with the second package, comprising part of the data request on the random access.

An important technical advantage of the present invention is that the part with the signature of the request for random access can also serve as the pilot signal by providing additional energy for channel estimation during the transfer of part of the data request.

Another important technical advantage of the present invention is that additional energy is provided with the request for random access to secure enough high-quality coherent mportant technical advantage of the present invention, that by transferring part of the signature request for random access in parallel with part of the data request, the amount of signaling overhead is reduced compared to previously known approaches.

Still another important technical advantage of the present invention is that there is no need to increase the elevated energy for rapidly changing channels.

A brief description of the drawings a More complete understanding of the method and device of the present invention can be achieved from the following detailed description with reference to the accompanying drawings, in which: Fig. 1 depicts a diagram illustrating the structure of the data block for the packet random access; Fig. 2 depicts a block diagram of a device that can be used in a mobile station for generating and transmitting packet random access, is illustrated in Fig.1; Fig. 3 depicts a block diagram of the detection section (for one antenna) receiver base station random access, which is primarily used to evaluate the synchronization of the beams of the received signal;
Fig.4 depicts a simple block diagram of the adder, which can be used for the first channel (quadrature of detektivagentura random access, which can be used for demodulation part with a data field of the packet random access;
Fig. 6 depicts a diagram illustrating the structure of a channel packet random access message format the General physical ascending channel, which is formatted in accordance with the previously known structures of the data block;
Fig.7 depicts a diagram that shows an exemplary format for General physical upstream channel in a communication system with random access, which is structured in accordance with a preferred embodiment of the present invention;
Fig. 8 depicts a simple block diagram of an exemplary device that creates a package that can be used to implement a preferred embodiment of the present invention; and
Fig. 9 depicts a block diagram of a suitable section of a cellular communication system, which can be used to implement a preferred embodiment of the present invention.

Detailed description of drawings
The preferred embodiment of the present invention and its advantages will be better understood when referring to the drawings, shown in Fig.1-9, in which the same numerals are used to designate the same is receiving the present invention, provides a new format for General physical upstream channel in a mobile communication system with random access, thus the mobile station transmits the first packet comprising a predetermined combination of signatures, in parallel with the second package, comprising part of the data request on the random access. Therefore, in addition to its other benefits, the part with the signature of the request for random access can also serve as the pilot signal by providing additional energy for channel estimation during the transfer of part of the data request at the same time reducing the number of existing above-ground signaling. This extra energy is particularly useful to ensure sufficient high-quality coherent detection part of the data request in a rapidly changing environment of the radio channel.

Essentially, Fig.7 depicts a graph that indicates the format pattern for General physical upstream channel in a communication system with random access, which is structured in accordance with a preferred embodiment of the present invention. As shown, the part with the signature of the request for random access p (for example, shown in the shaded area) to the energy in the Overworld (signature) part much more than the ratio of the energy in part of the data to the elevated energy of the format of the channel shown in Fig.6.

Fig. 8 depicts a simple block diagram of the device generating the sample package, which can be used to implement a preferred embodiment of the present invention. This embodiment may be implemented as a method, and the generated packet that should be transmitted on the shared physical uplink channel under control of the microprocessor placed in the mobile station. An example of such a mobile station is shown in Fig.9, which shows a block diagram of a suitable section of a cellular communication system, which can be used to implement a preferred embodiment of the invention.

The system 100 includes a receive / transmit antenna 112 and the transmitting-receiving unit 114, and many mobile stations 116 and 118. Although shown only two mobile stations, Fig. 9 serves only as illustration, and in accordance with the present invention, the number of mobile stations may be more than two. Before generating and transmitting a data block of the request for access of a mobile station (e.g., 116) synchronizes the aqueous interval of information broadcasting/pilot channel of a base station. The mobile station also samples the number of time intervals to be processed from the information broadcasting/pilot channel that should be used by the base station for a bunch of reply confirming acceptance of the message with the number of the time interval to ensure that the ACK message will correct mobile station. Details synchronization of the mobile station with the base station can be found in the '501 application.

The target base station also transmits to the requesting mobile station(s), for example, the top-down broadcasting channel, each unique extension code random access and long code associated with each of the sectors, honeycombs, etc. defined by the base transceiver station. For example, these unique extension code and a long code may be codes gold (Gold or Kasami codes (Kasami). The mobile station stores information about the code expansion and the long code in memory (not shown in detail), which must be found and used by a mobile station for extension fields signatures and data fields that are created packages of requests for random access. Finally, the base station also parade is Gator, related fields of signatures that can be used to facilitate recognition of different sectors, hundred, and so on,

As shown in Fig.8, an exemplary device 200 to the mobile station includes a unit generating signatures 202 and the data generation unit 204. Unit 202 includes a mixer signal 208, which extends the signature i" 206 (for example, which was selected from the area of the internal memory in the mobile station) using a specific code extension 210 for a given cell/sector (for example, selected from the internal memory area). Alternatively, the extension code may be, for example, specific to the base station or global to the system. Thus, the block 202, generating a signature, generates a specific cell/sector part of the signature packet random access, which must be passed. The format is part of the signature may, for example, be formed by expansion of the field signatures for the entire block of data General physical upstream channel or it can be repeated several times within a block of data.

Part of the data corresponding package random access, which must be transmitted in parallel with part of the signature is generated by the code extension 216, associated with the "signature i". Then the resulting data field of the corresponding packet random access is expanded using the cascade code mixer 218. This cascade code can be generated, for example, by adding modulo 2 (via mixer 218) associated with the signature short code 216 with sector-specific long code extension 220 (for example, selected from the internal memory). The length of the resulting field data that should be transmitted, can be flexibly selected by the mobile station. For this exemplary embodiment, the expanded field signature and the extended data field can be compacted (for example, to have a temporary seal) to be transmitted in parallel from the mobile station.

Although the preferred embodiment of the method and device of the present invention has been illustrated in the accompanying drawings and described in the foregoing detailed description, it should be clear that the invention is not limited to the described embodiment, and can be of numerous rearrangements, modifications and substitutions within the invention set forth and defined in the following claims.


The formula from the population of direct sequence signals, contains the stages at which the transfer data field including said data, on the said physical channel during the time period defined in advance duration and transmit in parallel with field data field signatures on the said physical channel during the mentioned period of time defined in advance duration, and the signature included in the said field signature, extend through the first of a predefined code and said data included in said data field, extend through a second code associated with said signature.

2. The method according to p. 1, in which the length of the mentioned field signature set almost equal to the width of the time interval for transmission.

3. The method according to p. 1, in which the length of the mentioned data fields selectively change.

4. The method according to p. 1, in which field signature contains at least one of the many combinations of signatures.

5. The method according to p. 1, which referred to the physical channel includes a General physical uplink channel.

6. The method of data transmission on the shared physical channel system multiple access with code extension signal direct sequence containing this is parallel with the said data field, these field signatures extend through a pre-defined code and said data field extend through the code associated with the said field signature.

7. The method according to p. 6, in which the mentioned field signatures are selected from a predefined range that includes at least one signature.

8. The method according to p. 7, which referred to a certain pre-series contains orthogonal series.

9. The method according to p. 6, in which the mentioned field data and field signatures scrambling through a predefined scrambling code.

10. The method according to p. 6, further containing a transfer operation mentioned field signature and the above-mentioned field data from the mobile station.

11. The method according to p. 10, in which the mentioned field signatures further comprises a pilot signal.

12. The device that generates the package containing the tool to generate code signatures, means for expanding the mentioned code signatures using code extension associated with certain pre-sector or hundredth, a tool for creating data fields, and means for expanding the mentioned fields using a code associated with the said code signature.

13. The device according to p. 12, further steriade the data.

 

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FIELD: radio communications.

SUBSTANCE: proposed method intended for single-ended radio communications between mobile objects whose routes have common initial center involves radio communications with aid of low-power intermediate transceiving stations equipped with non-directional antennas and dropped from mobile object, these intermediate transceiving drop stations being produced in advance on mentioned mobile objects and destroyed upon completion of radio communications. Proposed radio communication system is characterized in reduced space requirement which enhances its effectiveness in joint functioning of several radio communication systems.

EFFECT: reduced mass and size of transceiver stations, enhanced noise immunity and electromagnetic safety of personnel.

1 cl, 7 dwg, 1 tbl

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