Radiophone system for groups of distant subscribers
FIELD: radiophone groups servicing distant subscribers.
SUBSTANCE: proposed radiophone system has base station, plurality of distant subscriber stations, group of modems, each affording direct digital synthesizing of any frequency identifying frequency channel within serial time spaces, and cluster controller incorporating means for synchronizing modems with base station and used to submit any of modems to support communications between subscriber stations and base station during sequential time intervals.
EFFECT: enhanced quality of voice information.
12 cl, 11 dwg
The scope of the invention
The invention relates to radiotelephone systems for many stations remote subscribers, and more particularly to radio systems in which some of these subscriber stations located in the immediate vicinity, i.e. the groups.
Radiotelephone system containing a base station for servicing remote subscriber stations, described in U.S. patent No. 5119375. In this system, each subscriber station is equipped with a radio that receives from the base station commands to tune to a specific channel and use a specific time interval within the duration of the conversation. Transmission over the air with a temporary seal was used for communication from the base station to the subscriber stations, and transmission with multiple access with time division (mdvr) channels for communication lines from the individual subscriber stations to the base station. Temporal partitioning of each radio channel at time intervals and compression of speech signals allowed each RF channel to support the number of voice channels equal to the number of time intervals. Analog voice signals into switching telephone network (PSTN) and from her first converted what was asociality in komandirovannye (M-law digital sampling pulse code modulation (PCM) at a transmission rate of 64 KB/sec. Before transmission over the air digital sample were subjected to speech compression to reduce speed and voice with 64 KB/s to 14.6 KB/sec using residual excited encoding with linear prediction. Required that the speech codec and the modem were specialized for a particular frequency and time interval during the duration of the call.
While the above system has worked quite satisfactorily, allowing you to make phone service, particularly in areas where there are no wired communication lines, an unexpected increase in such telephone services has led to situations in which subscriber stations are in close proximity to each other. Initial efforts to reduce the cost on one line when the service groups such close subscriber stations were aimed at uniting the costs of installation and maintenance of individual subscriber stations through the sharing of common equipment, such as housing, power supply, RF power amplifier and the antenna. Thus, in a group of closely spaced subscriber stations, each of which could have access to the RF channel, the only broadband RF power amplifier could be used to serve this group. About which, however, still needed to each subscriber line had its own modem and radio transceiver. The output signals of the individual transceivers were submitted for a total RF power amplifier, which was to manage a maximum capacity equal to the sum of capacities of all of the transceivers in the group adjacent subscriber stations that could be simultaneously active on the same time interval. Obviously, it would be desirable to further increase efficiency in comparison with the results provided by the patent 5119375, the reduction in maximum and average required power especially in remote areas, maintenance-using capacities of solar cells.
The essence of the invention
According to the principles of the invention the cost of the communication line to reduce physically compact groups of subscriber lines by ensuring that lines the inside of this group is not only a common power source and the RF power amplifier, but also the General modem, synchronization, intermediate frequency (if)conversion functions with increasing and decreasing frequency, and a controller that achieves a significant concentration of resources. In such a system provided by a small number of modems to service multiple subscribers in a physically very close to the band, referred to as the cluster is ohms or more specifically a modular cluster. In the illustrative embodiment, the subscriber circuits and modems are modular printed circuit Board that is inserted into the switching shield using the backplane to distribute information on the temporal characteristics and data among blocks. Any of the modems can be used to manage calls for multiple subscribers at successive time intervals.
A feature of the invention is that the selection from a common pool of modems with fast frequency modem call control is adjustable to save power consumption in two ways. First, the new modem preferably does not for use in processing the call up until all time slots on the active modems are challenges that have not yet selected modems to remain in power-saving "lower power" state.
Secondly, the number of calls using the same time interval (at different frequencies), is adjusted to reduce the maximum power consumption of the RF power amplifier.
Another feature of the invention is the elimination of synchronization delays when necessary classes in the state of low power modem to use it on the call. As soon as the synchronization time interval with b the gas station is installed for the first modem in the pool when this cluster (group) the synchronization information becomes available to other modems, mainly through the backplane, under the control of the cluster controller based on a microprocessor. Therefore, all modems with reduced capacity immediately available without any delay to obtain synchronization with the cycle of time-division base station.
Another feature of the invention is the classification of state synchronization modems in accordance with multiple classification parameters and obtaining the confidence level (probability) for each active modem, reflecting the reliability of the synchronization parameters, and the distribution of timing information from the modem with the best confidence level.
Brief description of drawings
The preceding and other objects and features of the invention will be more apparent from the following description, illustrated by the drawings, which represent the following:
figure 1 - block diagram of the modular cluster having a common pool of modems with fast frequency for processing the group of subscriber units;
figa is an illustration of the connection of the subscriber line circuits and modems in the equipment exchange time intervals;
figw - RF cycle multiple access with time division (mdvr) ka is Alov, allocated to time slots of 16-point phase manipulation;
figs - RF cycle mdvr allocated to time slots quadrature phase manipulation;
fig.2D - distribution of tasks between time intervals mdvr and PCM buffers;
figure 3 - schematic circuit elements module modem with fast frequency agility;
4 is a block intermediate frequency (if) modem with fast frequency;
5 is a block diagram of the synthesizer of the transducer block increasing/decreasing frequency;
6 is a frequency synthesizer and a noise shaper for receiving part of the modem;
Fig.7. scheme of synthesis frequencies, modulation and noise shaper on the intermediate frequency for the transmit side modem;
Fig diagram of the impulse generator for modular cluster.
Description of embodiments of the invention
Figure 1 presents the block diagram of the modular subscriber cluster, remote from the base station (not shown). Subscriber cluster named "modular"because linear circuit 100 and modems 400 consist of interchangeable blocks. Therefore, the number of removable subscriber line circuit 100 will depend on the number of subscribers in the area, and the number of interchangeable modems 400 may be selected to ensure the processing workload expected from the number of linear circuits 100. Linear chain of 100 mA is conducted on chetvertnyh linear modular printed circuit boards 101-108, each serving four subscriber lines. Eight such chetvertnyh line modules provide the functionality of a closed system of automatic control group of 32 subscriber lines, and the circuit 100 may contain many linear groups.
Each linear chain on each chetverina linear module 101-108 causes the emergence of a specialized time frame pulse code modulation (PCM) the PCM transmission path of the speech signal 200 and in the path of the call (signaling) 201. Modules 101-108 include codecs speech signals (not shown) for encoding an analog voice signal of the subscriber circuit to transmit in path 200 PCM data. Information signaling for subscriber circuits served in the tract alarm 201 through the interface schema subscriber line. Can be used for encoding according to the law M-kompaktirovaniya or the law And kompaktirovaniya.
The specific connection of one of the modems 400 for processing a call from one specific chain of linear chains or a specific chain of linear circuits with one of chetvertnyh line modules 101-108 is made through the blocks sharing time slots 310 and 320 on the command cluster controller 300. The exchange unit 320 time intervals PCM data passes the speech samples between the PCM transmission path receivesocial 200, servicing linear modules 101-108, and PCM channel voice signal 220 serving a pool of modems 400. The exchange unit 310 time intervals call transmits the information of the call between the path of the call 201 serving the modules 100, and route the call 221 serving a pool of modems 400.
For a telephone conversation requires two RF channel, one for transmission from base station to the subscriber (the"direct" channel) and one from the subscriber to the base station (reverse channel). The frequency of forward and reverse channels are provided by the office of telecommunications and in a typical case can be separated from one another by intervals of 5 MHz. The path of propagation of the direct channel, taken in the cluster from the base station, can be traced from the cluster of antennas 900 and antenna switch 800 to block synthesizer and transmitter raise and lower frequency 600. In the transducer block 600 RF signal is limited, filtered in the frequency band converted to the lower frequency of band RF signal at a frequency of 450 MHz, 900 MHz or other high or ultra-high frequency signal to an intermediate frequency (if) in the range of 26-28 MHz. This if signal is supplied to the modem 400, which processes this signal to feed to the subscriber line circuit through the blocks sharing time slots in the cluster controller 300.
Each of the modems VK is uchet the digital signal processor bandwidth of the modulating signals (smpeg, DS/CC) and the modem processor (smpeg, DS/D). In the transmit direction of the direct channel processor modem DS/D demodulates the if signal received from the transducer block 600, and transmits the data to the digital signal processor DS/CC, which converts the demodulated data encoded on M-law or A-law kompaktirovaniya signals for transmission through the block 320 exchange time intervals to the line modules. The digital signal processor DSP/BB modem interfacing with the modem processor DSP/D interface to directly access memory (smpeg, D) and paths PCM data through the serial port of the processor. In the transmit direction in the reverse channel digital signal processor DS/BB converts encoded by M-law or A-law kompaktirovaniya PCM data from the PCM highway 500, in linear form, compresses these linear data using residual excited coding linear prediction (BELP) and passes through the D compressed data to the digital signal processor DSP/MDM, which modulates the signal for transmission in the time interval of the radio channel.
As shown in Figa, each of the modems 400 and each of the line module 100 has four specialized types of temporary intervalof in the exchange unit 320 time intervals PCM data for non-blocking access. Each modem on the I two adjacent PCM intervals in the PCM time slots 0-15 and for two adjacent PCM time slots in the PCM time slots 16-31. For example, for a particular call exchanger of time intervals S1 320 connects the linear chain 0 linear module 101 to channel 1 modem 1 and the linear chain 1 linear module 101 with channel 0 modem 1 etc. Blocks sharing time slots 310 and 320 provide duplicate sampling period duration of 125 μs, consisting of 32 time slots, data rate 2,048 MB/sec. During each PCM interval of 125 μs linear modules can send 32 8-bit bytes of data in the exchange unit time intervals 320, and each modem can receive 4 8-bit bytes on the serial port of the processor group signal, Packed together in the form of two 16-bit layers. Each 16-bit word causes the interrupt signal on the serial port of the processor group signal. Upon receipt of the interrupt signal, the processor group signal determines whether a pair of PCM samples contained in this 16-bit word, the intervals 0 and 1 or interval 2 and 3. Similarly, each time the PCM interval of 125 μs four speech channel PCM data, Packed together in the form of two 16-bit words can be sent from the serial port of each processor group signal to the exchange unit time intervals 320 for delivery to the line modules.
RF cycle temporary seal on the base station display is on Figv and 2C with a duration of 45 MS each. Cycle 16-position FMN Figv has four time intervals, each lasting τand each time interval is able to carry different frequencies provided by the forward and reverse channels of the call. On Figs RF cycle of the same length provides an implementation of forward and reverse channels two calls, modulated by QPSK quadrature. It is clear that the scheme temporary seal can provide four calls with 16-position FMN or two calls quadrature FMN.
Fig.2D illustrates the synchronization of tasks in a cluster in the transmission of information between the considered scheme mdvr using call / QPSK modulation and PCM channels. String (1) represents the buffers for the reception of two quadrature modulated FMN time intervals of the direct channel, Rx1 and Rx2, cycle mdvr. Demodulation begins as soon as the buffer receives the first half, Rx1a, time interval. Line (2) represents the buffers ready to transmit in two quadrature modulated FMN time intervals reverse channel TX1 should be and TX2, cycle mdvr. Note that in the cluster time intervals reverse channel offset time intervals of the direct channel, so you can avoid the cost of the antenna switch. In addition, the reverse channel subscriber BL is ka shifted so he will be received at the base station at an appropriate time depending on the distance between a subscriber's point and the base station. Line (3) and (4) on Fig.2D denote buffers in static NVR (figure 3) modem, which store the PCM data words are sent to the exchange unit S1 320 speech time intervals and from it (Figure 1).
In normal voice mode, the modem processor DS/MDM demodulates the received symbols of the downlink channel, packs them in a buffer in static NVR modem SR/D (Figure 3) and sends the contents of this buffer to the processor group signal DS/BB for RELP synthesis (extension). The processor group signal encodes the enhanced data according to the M-characteristic or a characteristic and transmits them to the bus PCM data for delivery to the line modules. Code word speech signals are transmitted in each cycle during an active voice mode. The code word is at the beginning of the data packet between the header and the speech data in both forward and reverse channel. Code word speech signals direct channel contain information that can be used to adjust transmit power and synchronization. Information local subscriber circuit (i.e. the call, hang up phone call, the separation of the direct channel) can also be entered in these code words. Code word backward channel contain is the information about the local subscriber circuit and the communication quality of the downlink channel.
The code word of the speech signal of the direct channel is decoded by the processor of the modem (DS/D). This code word contains information on adjusting the transmit fractional synchronization, adjusting the transmitted power level and adjusting the local circuit. Information about fractional synchronization and adjustment of the power level averaged over a cycle, and the average adjustment is performed at the end of the cycle. Information management local chain is stored locally, and changes in the condition of the chain are detected and reported to the cluster controller. Managing local circuit also causes the modem to transmit the control signals of the linear chain bus signaling. The code word of the speech signal return channel includes a local chain, which is the cluster controller and the base station to monitor call progress.
Processor modem SD/MDM performs filtering with a finite impulse response and automatic gain control of the received samples in the maintenance program with the interruption of the received symbols. The program of the demodulator in the process of the modem is called when the reception into receive buffer half time interval information group spectrum of transmitted signals. The demodulator operates at half of the interval data and transmits the Packed output data is in the processor group signal DSP/BB for RELP synthesis. Data transfer to the processor group signal and it is adjusted so that the input queue RL filled before you will need the relevant data synthesis, and output queue RELP emptied before it receives output from a new analysis (compression). During demodulation are performed automatically adjusting the frequency of the (ARCH), automatic gain control (AGC) and processors tracking bits to maintain precise synchronization with the base station.
Clearly, there is a mixed mode of operation in which some intervals may use modulation 16-position FMN, whereas other intervals may use modulation QPSK quadrature.
Synchronization with the base station
Before applying RF channel for communication between the base station and the cluster, the cluster must be synchronized with the cycle of time intervals RF used by the base station (not shown). According to the invention one or more modems 400 receives commands from the cluster controller 300 of synchronization with the frame synchronization RF base station by searching for the frequency channel carrying the radio channel used by the base station. The cluster controller 300 includes a Central microprocessor control 330, such as the 68000 series processor company is Motorola, which sends the management information via the bus CF (Central processing unit) to microprocessors in the modem 400. When applying power cluster controller 300 loads the data appropriate software and source data in the modem 400. After finding the channel frequencies of the modem must be synchronized with the time interval of the base station by decoding the unique words (radio control RCC). As described in the aforementioned patent 5119375, channel RCC differs from other channels to the fact that he has an extended guard interval in its time interval and includes DS TO the modulated unique word of 8 bits. To reduce the possibility of cancellation of the call, if there is no modem with an active time interval RCC and it becomes necessary to provide a time interval R another modem, the time intervals are provided in the active modem so that the time synchronization interval (R) (called Rx0, where four time intervals are Rx0-Rx3, or Rx1, where four time intervals represent Rx1-Rx4) is the latest, which should be filled.
When you start it is assumed that all modems 400 is not synchronized with the RF cycle 45 MS to the base station. During the time interval 0 this RF cycle, the base station transmits the message which begins R on a given RF channel, which when taken in a modular cluster will be decoded, by synchronizing the cluster with RF cycle time interval of the base station for all RF channels. Until you achieve synchronization with the base station, each modem generates its own local RF cyclic synchronization. Then the cluster controller 300 instructs one or more modems to search RCC transferred to the base station on different RF channels until, until a match is found R or until all channels will not be subjected to search. If after searching all channels R was not found, the controller gives the command again to start the search. When one of the modems finds this R (radio link control), the controller refers to it as R modem and distributes its timing information to all other modems through the frame synchronization signal using a backplane.
When searching R interval the channel number used by the modem for the digital frequency tuning of the local oscillator is a direct digital frequency synthesis (DDFS), for example, in the range of 2 MHz. There are two stages to capture the modem R channel: coarse frequency detection channel of communication and finding the "AM " holes", part of the time channel R, in which the number of symbols transmitted by the base station, does not fill the entire time interval. Rough zahwah the frequency based on the execution of the Hilbert transform of the spectrum R channel, which gives the correction to the frequency of the local oscillator. This continues until the energy in the upper half of the spectrum is close to the energy in the lower half.
After the rough seizure frequency, for example, up to 300 Hz versus frequency of the communication channel search AM the holes. The number zero signal is transmitted before the data RCC. AM a hole is detected by monitoring the amplitude of successively received symbols. When the detection of 12 consecutive null characters, the modem displays AM-stopsignal indicating the beginning R interval and the beginning of the cycle mdvr. This is roughly synchronizes the timing of the modem baseband with temporal characteristics of the base station. Synchronization should be done only once, since the radio channel is shared by all modems baseband signals in a modular cluster. The frame synchronization signal is transmitted from one modem to all the other modems in the cluster by means of the signal transmitted on the conductors in the backplane. When searching R if AM found a hole up to 3 symbol periods from the beginning of a cyclical token, rude capture is completed. Detection of a unique word within this cycle provides the modem synchronization information, which is used to synchronize the local hronia the project for this modem up to exactly 1 character with the base station. The modem is in the synchronization state when receivingas long as he continues to receive and correctly decode the unique word. Once synchronization is achieved, can be applied modulation 16-position FMN, corresponding to 4 bits per symbol, quadrature modulation, corresponding to 2 bits per symbol, or combinations thereof.
Although all modems are capable of receiving the radio signal control (R) base station to synchronize to it, only one modem must do this because the modem is selected as the cluster controller may synchronize together with other modems through the frame synchronization signal using a backplane. The selected modem is the source of the output frame synchronization signal and all other modems will accept this signal as the input frame synchronization signal.
When connecting the modem to the Central processor processor modem DS/D transmits the command to DDF 450 (3) to attempt to synchronize the local cyclic bronirovanie with the signal backplane. Bronirovanie DDF 450 each modem at this point, regardless of bronirovania each of the other modem. First, the DDF block 450 receives a command from the CPU DS/DM to search for the signal backplane for the implementation of the synchro is Itachi. If the synchronization signal backplane is present, DDF will synchronize its frame synchronization signal from the signal backplane, and then disconnect from the signal backplane. Thus, the signal backplane is not served directly in the scheme bronirovania modem, and only combines the internal launch of the modem with the received signal cycle. If the synchronization signal backplane is missing, it is assumed that the modem is first activated cluster controller, and in this case, the cluster controller 300 instructs the modem processor DS/D to search for RCC and transmits the message bronirovanii modem cluster controller.
Then the cluster controller 300 instructs the modem processor DSP/MDM to demodulate DS TO the signal in the channel R. Channel demodulation of the if signal received from the Converter 600, can be carried to the inverter module of the modem, where it is again filtered by bandpass filter and is converted to a lower frequency with the formation of a flow of information with a speed of 16 kilosymbols per second. DS modulation used in the channel R, represents the modulation type one bit per symbol. Signals R received from the base station must be demodulated and decoded before sending to the cluster controller. Only messages with gnly), which is addressed to the cluster controller, have a valid CRC (control cyclic redundancy code) and is the signal of a batch type or heartbeats are sent to the controller. All other messages are discarded. The confirmation signal indicates the correct reception of the previous signal R. Signal addressed to the cluster controller, if the identification number of the subscriber (SLD)contained in this message is consistent with the SID of the cluster.
According to Figure 3, the if signal with a speed of 16 kilosymbols per second from the inverter circuit (4) is fed to an analog-to-digital Converter 804, which is sampled with a rate of 64 kHz using a synchronization signal received from DDF block 450. Analog-to-digital Converter 804 produces quadrature discretization in bandwidth with a sampling frequency of 64 kHz. Quadrature discretization in the passband is described, for example, in U.S. patent No. 4764940. The output of inverter 804 is formed by a sequence of complex signals, which has some temporary distortion. The output signal of the inverter 804 (Fig) enters the stack of received signals (RFIF0) DDF block 450. Processor modem DS/D reads the contents of the block RFIF0 and performs the operation of a complex filter with finite impulse response, which removes viennoiserie, input quadrature discretization in bandwidth. After removal of the temporary distortion signals demodulated processor DSP/MDM.
During the demodulation of the R the modem processor DSP/MDM are locked loop frequency, automatic gain control and tracking bits to maintain the accurate synchronization of the cluster to the base station. Adjusting the transmission time and power level are performed in accordance with information contained in a received signal R. The processor DS/D analyzes the demodulated data and detects the signal R, which includes status bits of the communication channel and the data of 96 bits, which include the identification number (SID). Processor modem DS/MDM also recognizes whether this SID to one of the subscriber line circuits in the cluster.
If the received message is a message for this cluster, it is passed to the cluster controller 300, which interprets the command R. Direct messages R include message retrieval call, establishing a connection by a call, an indication of the free line and a self-test. Back RCC include receiving a call, request a free line, the scan results and a request for the call. If the message R is a message retrieval call, the cluster controller on the I which is included in this message, will generate a message about receiving a call for transmission back to the base station. From the message on receiving a call, the base station determines the offset in time between the cluster and the base station, then the base station sends character information to adjust the timing to the cluster in the following message RCC, which is a message about the connection on call.
If the message RCC is a message about the connection on a call, the information contained herein is a command for the cluster controller on what adjustments to make in character synchronization, do I need to adjust the power level fractional bronirovanie and what channel to use for the rest of the call (the channel number, the number of the time interval of the temporary seal will be applied / QPSK or 16-way QPSK modulation and what is the type of subscriber line).
The first modem detected RCC, referred to as modem RCC, and its frequency shift, gain control and information about the beginning of the cycle are considered correct and can spread to other modems. The cluster controller receives information about the channel number and decides what modem should receive the command to configure this channel to process the rest of the call.
The final stage in d is stijene total synchronization is successful installation of the speech channel. When you install the speech channel, the last two parameters synchronization is correct: synchronization of transmitted symbols and fractional synchronization of transmitted symbols. At this point, when you activate the cluster controller to another modem all the necessary synchronization information is available to provide it with this modem that facilitates and accelerates the installation of the speech channel. Confidence level (confidence level) is calculated to assess the timing information of each modem. The cluster controller adjusts the confidence level for each modem, as soon as a change occurs in the synchronization state, the communication quality or AGC at the reception. The cluster controller finds the modem with the highest confidence level and distributes its sync options on other modems.
When the modem commands from the cluster controller of getting into voice mode, the modem first tries to perform the cleaning. Cleaning is a process of precise synchronization bronirovania transmission modem and power level with bronirovanie base station. The cleaning process is regulated by the base station. The base station and modem share special packages cleaning up until the base station does not complete the cleaning process while achieving the acceptable degree of synchronization. Then the modem returns to normal voice mode. If the base station stops the cleaning process, the modem will terminate the call, go into silent mode and inform the cluster controller. Packages are cleaning DS packets, formatted similarly R packages. The cleanup packets detected by the presence of unique words cleanup. The modem is in voice synchronization, when the unique word clearing is found with a zero offset. Code word speech signals in forward and backward linkages have control byte code word speech signals attached for error detection. The modem will report a loss of synchronization if 9 consecutive frames are received with errors of speech code words. In this case, the cluster controller is in recovery mode and in this mode until then, until you found a good code word or until the modem will not receive a command to exit this mode and enter the silent mode.
Based on the synchronization status of the cluster controller 300 determines the correctness of the synchronization parameters, provided by the modem. The table below shows which parameters are correct, based on the current synchronization status of the modem. "X" in the table indicates that the parameter is of the rights is determined as being.
The status of the sync.
|The frequency shift||The time symbol.||Time drobn.||TxPLC programming. logich. control when passing||RxAGC AGC when receiving||SORF|
|Sync. transmission (RCC)||X||X||X||X|
The word confidence level of 12 bits is calculated by the modem to reflect the reliability of the synchronization parameters set by the modem. The word confidence level is composed by the concatenation of bits representing castaneocoronata speech and receive modem, the bits identifying the communication quality parameters and derived AGC, as shown in the following table.
|The allocation of bits||11||10||9...8||7...0|
|Region||Recev. sync.||Synchronization when receiving (RCC)||The quality of the connection||AGC when receiving|
Single bits 11 and 10 respectively show whether the modem or is not in sync speech and reception. Two bits 9 and 8 identify 4 levels of quality of communication, while the 8 bits designed for a level of automatic gain control, indicate the desired gain level.
The modem module. 3
The main components of the module of the modem shown in Figure 3. This module can serve up to 4 simultaneous full-duplex voice channels. Processing to dynamically manipulate all the functions required active channel is divided between the processor cluster controller 320 (Fig 1) and processors DS/D (processor modem) and DS/BB (processor group signal) in each modem (Figure 3). Processor modem DS/D serves filtering, demodulation and routing of incoming radio signals, formatting data before it is transmitted over the air and control the flow of data between them and the group processor DSP/CC. The processor group signal DS/BB performs processor-intensive tasks of compression and expansion of speech, and, in addition, serves PCM bus mates. In normal voice mode, the modem processor DS/D demodulates the received symbols, packages them in a host buffer and send the buffer to the speech data to the group processor DS/BB for RELP synthesis and transfer to a subscriber line circuit via the PCM bus. The modem processor DSP/MDM also receives the compressed speech from processor group signal DS/BB, formats it in the packages mdvr and sends to the shaping filter of the transmitted pulses contained in the DDF 450 for transmission over the air. This modem works with signals / QPSK modulation and QPSK modulation (and DS during cleaning) under control of the cluster controller.
Each of the processors DSP/BB and DS/D have specialized static NVR, SRAM/MDM and SRA/CC, respectively. However, the modem processor DSP/MDM can request access to static NVR SRAM/BB by activating its output classes direct access memory (DMA) and obtains such access through the data bus and address bus when activated by the processor group signal DS/BB output signal of the symbol confirmation direct access to memory (D).
As described in the patent 5119375, RPV in the base of a hundred the function stores the path of the radio signal and the time intervals, used, and distributes both frequency and time intervals for use in every call. Select the interval that is used the least number of calls so that the load of the call can more evenly distributed across all intervals. However, in accordance with an aspect of the present invention, related to the reduction of power consumed in the remote modular cluster, the call feature so that (a) reduce the number of active modems and b) to regulate the number of conversations simultaneously using the same time intervals. Further, although it is desirable to apply modulation using 16-point FMN in each time interval mdvr cycle, so that you can agree on four full call, it is also important to establish calls using quadrature FMN and keep alternating R interval, suitable for synchronization purposes. Therefore, the cluster and the base station must communicate with the distribution of time intervals to achieve these goals. The cluster keeps track of the available time intervals and the type of modulation used in each interval. Then the cluster prescribes the priority levels for each of the available interval and maintains a matrix of values of priority that takes into account that a) the regular temporarily the reception interval (usually the first time interval) on any channel must be designed to R synchronization, b) adjacent time intervals must remain accessible as possible, so if necessary you can distribute QPSK calls, and b) the time intervals should be provided for handling calls, if possible, without activating the modem low power or without interval, which is already used by a large number of other challenges. The program (in pseudocode) for achieving these goals is the following:
Program prioritization in time intervals
A list of 1 = all free time slots available on the active modems for 16S calls and QPSK calls.
List 1A = all available modems;
List 2 = List of time intervals, the use of which will not exceed the threshold number of calls using the same time interval in the cluster.
The list 2A = List minus 1 List 2;
List 3 = List of 2 minus time slots on modems with neighboring available (for calls QPSK) time intervals;
The list 3A = List of 2 minus time slots on modems that do not have neighboring available (for QPSK calls) time intervals;
List 4 = List of 3 minus time slots on modems that do not have available to synchronize the time of the second interval (interval 0 to RCC);
List 4A = List 4 minus time slots on modems that have available time interval for synchronization;
Mark list 4 as the first choice;
Note the list of 4A as a second choice;
Mark list 3 as the third choice;
Note the list of 3A as a fourth choice;
Mark list 2 as the fifth choice;
Note the list 2A as the sixth choice;
Mark list 1 as the seventh choice;
Note the list 1A as the eighth selection.
Described the program prioritization interval is called as soon as the cluster gets R signal search call from the base station, when the cluster is going to send a signal to the call request to the base station. When the base station responds with a message about enabling call containing the frequency, modulation type and the time interval that should be used, the cluster again executes the determination program of priority, to determine whether the selected RPV interval is still available. If it is still available, he is free of this challenge. However, if the time distribution of the intervals has changed, the call may be blocked.
An example of how the program is executed to determine priority under light and heavy load conditions, it may be useful. First, let's consider the following table, which illustrates the possible condition of the modems and sannich time intervals under light load conditions, just before one of the subscribers served this modular cluster initiates service request:
|Modem||The time interval|
The above table shows that the modem has 0 available intervals 2 and 3, the modem 1 has an available interval 1 and modem 2, 3, 4 and 5 have reduced power, and their time intervals are free. The cluster runs the program determine the priority of the intervals, which determines that the intervals 1, 2 and 3 in this sequence are the preferred intervals to provide for processing of the next 16S call and what to QPS calls preferred intervals are 2 and 0 in this sequence. Then the cluster sends the signal "call request" to the base station using RCC words and informs the base station about this preference. The table below presents the logical framework for each of the priorities:
|The priority interval 16S||Base||The priority interval S||Base|
|1||There is no higher power new modems; no increase in the maximum activity interval;|
QPSK intervals 2, 3 remain available;
R interval available.
|2||(Same reason as in the case 16S for intervals 2, 3)|
|2||New OPS challenges require a new modem||0||Requirements include a new modem|
|0||The request to activate the new modem|
Can be useful is another example. Consider the state of the time intervals among the modems 0-5 with a few heavier load conditions, as shown in the following table, where empty cells indicate available time intervals:
|Modem||Time the military int|
Providing time intervals shown in the following table, together with logical reasons:
|The priority interval 16S||Base||The priority interval QPSK||Base|
|3||There is no higher power new modems; avoids max activity interval; QPSK intervals 2, 3 remain available; RCC interval remains available||2||The only choice|
|2||There is no higher power new modems; avoids max activity interval; R interval available;|
|BUT the new QPSK is isow requires increasing the capacity of the new modem;|
|1||There is no higher power new modems; S intervals 2, 3 are still available, BUT max activity interval is exceeded|
|0||No upward. powerful. new modems; QPSK intervals 2, 3 are still available; BUT max activity interval is exceeded, and R interval is not available.|
Boost/step-down Converter 600
As shown in Figure 5, the forward channel radio signals from the base station receives in increase/Panigale Converter 600 through the antenna switch 800. The received RF signal passes through a low noise amplifier 502, filtered bandpass filter 503 is subjected to the attenuation in the attenuator 504 and is supplied to the frequency Converter 505, where it is subjected to the first conversion with decreasing frequency from 450 MHz RF band or 900 RF band to the if signal in the range of 26-28 MHz. The if signal passes through the amplifier 506, a band-pass filter 507, the amplifier 508 and the attenuator 509 and is fed to the splitter 510 for delivery to the entire pool of modems.
The modulated if signals of the backward channel from the pool of modems served on the unifier boost/step-down Converter 600 in the upper left corner of Figure 5, are subjected to an impairment att is noitora 521, filtered in bandpass filter 522, amplified in the amplifier 523 and fed to the frequency Converter 525, where the signal is converted with increasing frequency in the RF signal or RF band 450 MHz or RF band of 900 MHz. Then the RF signal is subject to attenuation in the attenuator 526, is filtered in bandpass filter 527, is amplified in the amplifier 528 and served on a broadband amplifier 700 high power, which sends the signal to the antenna switch 800.
The frequency converters 505 and 525 receive their reference frequency of the system phase adjustment (PLL) 540 admission and system PLL 550 during transmission, respectively. The PLL 540 generates the lo signal receiver at a frequency of 1.36 MHz from the signal produced by the master clock generator 560 frequency 21,76 MHz, divide by 2 and then by 8. The signal frequency of 1.36 MHz provides the reference input to the phase comparator PC. The other input of the phase comparator is provided by a feedback circuit which divides the output signal of circuit 540 for 2 and then at 177. Reverse feed this signal to the phase comparator determines that the output signal circuit 540 has a frequency, which in 354 times the frequency of the reference signal, i.e. 481,44 MHz. The output signal of frequency 481,44 MHz PLL 540 when the reception is served as an input lo signal on onecause frequency Converter 505.
The output signal of frequency 481,44 MHz circuit 540 also served as the reference input signal for the circuit 550, so that the chain 550 adjusted according to the frequency with circuit 540. Circuit 550 generates a transmitted signal of the local oscillator that has a frequency 481,44 MHz+5,44 MHz, i.e. it has a frequency that is shifted by 5,44 MHz up compared to the received signal of the local oscillator. For the circuit 550 signal 21,76 MHz oscillator main clock 560 is divided into 2, then again at 2 with the formation of a signal with a frequency 5,44 MHz, which is input to the reference signal of the phase comparator PC circuit 550. The other input of the phase comparator PC circuit 550 is filtered by a lowpass filter (LPF) differential frequency between the received signal of the local oscillator of the circuit 540 and the output signal of the generator, voltage-controlled (VCO) circuit 550. Output signal circuit 550 with its internal oscillator, voltage-controlled (VCO, VCO)represents the frequency 481,44 MHz + 5,44 MHz.
4, the FC part of modem
Figure 4 shows in detail the FC portion of the modem card from the digital parts (Figure 3). As shown in the lower right side of Figure 4, the received if signal from SVD 600 (Fig 1) is supplied through the lower terminal of the switch return circuit 402 4-pole bandpass filter 404 with the band from 26 to 28.3 MHz. Then the filter output signal 404 privaatsusele 406 and converted with decreasing frequency in the inverter 408, using the received lo signal having a frequency in the range from 15.1 MHz to 17.4 MHz. The output signal of inverter 408 is amplified by the amplifier 410 and filtered through an 8-pole crystal filter 412 with a center frequency of 10,864 MHz. The amplitude of the signal at the output of the filter 412 is adjusted by the AGC circuit 414. The gain of the AGC circuit 414 is governed by the signal VAGC from DDF SI (specialized IP) 450 (Fig 3). The output signal of the AGC circuit 414 is then converted with decreasing frequency Converter 416, using the reference frequency 10,88 MHz. The result is a sequence of FC data transmitted at the rate of 16 kilosymbols/s, which passes through the amplifier 418 and arrives at the receiving input of the inverter port circuit in Figure 3.
The scheme shown in Figure 3, generates the lo signal RxDDF, which is filtered 7-pole filter 432, and then amplified by the power amplifier 434. The output signal of amplifier 434 is again filtered by the low pass filter 436, the output of which is amplified by the power amplifier 438 and then mixed to obtain the if signal in the mixer 408.
As shown in the right part of Figure 4, the amplifier 420 receives a signal oscillator with frequency 21,76 MHz and delivers it to the splitter 422. One output of splitter 422 is doubled in frequency by a frequency doubler 424, the output of which is limiting what is in the limiter 426 and is converted to the level of transistor-transistor logic circuits logic element 428 and is inverted again by the logical element 430. The output signal of the logic element 430 is fed to the circuit in Figure 3 as a reference clock frequency 43,52 MHz.
The other output of the splitter 422 passes through the amplifier 454 and the attenuator 456 and served on a heterodyne input (L) mixer 444. Mixer 444 converts with increasing frequency modulated if signal xD1F with scheme 3 after filtering in a low pass filter 440 and the attenuation of the attenuator 422.
The output of logic element 428 is also connected to the input of inverter 460, the output frequency of which is divided into 4 frequency divider 462 and is then used as the local oscillator for conversion with decreasing frequency of the output signal of the AGC block 414 mixer 416.
Function return circuit is provided by the serial combination of switches 450 and 402 and dummy load 458, so that the output signal of the D1F schema in Figure 3 can be fed back to the input Rx1F for verification purposes when submitting test sequences to compensate for distortion of signals, for example, in a quartz filter 412.
The diagram in Figure 3 provides a modulated inverter output frequency with 4.64-6,94 MHz, which is filtered 7-pole filter 440 and is attenuated by the attenuator 442. The output signal of the attenuator 442 is fed to a mixer (frequency Converter) 444, where it is converted with increasing cestocide frequency in the range of 26.4 MHz to 28.7 MHz. The output signal of the frequency Converter 444 is supplied to the amplifier 446, the output of which is filtered 4-band bandpass filter 448 and is supplied to the switch 450, which is controlled by the output signal LBE harness the return circuit from the schematic in Figure 3. When performing testing conclusion LBE supplied, causing the switch 450 to connect the output of the filter 448 with the upper part of the absorbing load 458 and connecting the switch 402 to connect the lower part of the absorbing load 358 with a bandpass filter 404 for testing using the reverse chain. This test is performed using test sequences to compensate for distortion of signals in quartz filter 412 Yves other circuits of the modem.
If testing using the reverse circuit is not performed, the output of switch 450 is connected to the programmable attenuator 452, which can be programmed to one of 16 different levels of attenuation of the signal level adjustment of the transmitted power, PLC, from the diagram in Figure 3. The output signal of the attenuator 452 contains TX 1F R signal which is fed to the upper left side BSVD (Figure 5).
6, RxDDS - Generation digital intermediate signal receiving channels
The exact intermediate frequency to adjust during a time interval of reception determine, to the Yes cluster controller CC (Figure 1) tells the modem, in which RF channel is to search for the RCC signal. While receiving messages R conduct accurate frequency setting and synchronization. Fine tuning perform at the level of the inverter with the chain drive phase diagram RxDDS DDF modem (Figure 3), shown in detail in Fig.6. The frequency range of the inverter formed of the repeating accumulation (with the frequency of the digital oscillator clock FC) number, which represents the jump of the phase in the drive phase. The modem processor DSP/MDM via data bus DS/D (3) first generates a 24-bit integerin the circuit RDDS. This number is connected (as will be described later) is required if necessary for demodulation of a particular incoming signal on the principle of interval during interval". 24-bit integeris loaded into one of the four registers R16-R46 in the left side of Fig.6. In the illustrative embodiment that utilizes a 16-bit processor, 24-bit number frequencyserved in 16-bit and 8-bit segments, however, to simplify the illustration shows that a 24-bit number included in the composite 24-bit register. Each of the registers R16-R46 is intended for one of the time intervals of the reception. Because R message is expected in the first RX time interval, 24-bit number is loaded into the corresponding one of the couple is ex registers R16-R46, for example, in register R16. With appropriate reference to the first RX of the time interval the contents of register R16 is provided to the register synchronization 602, the output of which is then fed to the upper input of the adder 604. The output of the adder 604 is connected to the input of the register memory 606.
The lower input of adder 604 receives the output signal of the register 606. Register 606 is synchronized 21,76 MHz DDS generator clock, and its contents, respectively, periodically again supplied to the adder 604.
Periodic re-supply of the contents of register 606 to the adder 604 causes the adder 604 to keep score of the number oforiginally obtained from the register R16. In the end, the adder 606 reaches the maximum number that it can support, then it is overloaded, and the countdown starts it again with a low residual value. This has the effect of multiplying the frequency of the DDS oscillator clock by a fractional value to the received if signal and local oscillator (lo) had this multiplied by the fraction of the frequency, when the sawtooth waveform. Since the register 606 is a 24-bit register that it is full, when its content reaches the 224. Therefore, the register 606 effectively divides the frequency of the DDS synchronizer 224and simultaneously multiplies her on
The accumulated phase from the register 606 is supplied to the circuit approximation of a sinusoidal signal 622, which is more fully described in U.S. Patent No. 5008900, "Subscriber unit for a digital radio system subscribers. Circuit 622 converts the sawtooth signal register 606 in sinusoidal form. Output circuit 622 re-synchronizes the register 624 and then fed to one input of filter noise shaper 632. The filter output signal 632 is supplied to another input of the adder 634. The output of the adder 634 is connected to the data input of the filter 632 and to the input of register Retiming 636. This filter noise shaper 632 variable coefficient is more fully described in U.S. patent No. 5008900. Characteristics of the noise shaper is governed by the principle of "interval for interval using 7-bit control field shaper noise, which combined with the least significant byte of the field reference frequency received from the bus DS/D, the noise Shaper can be enabled or blocked, can be selected up to 16 filter coefficients, the rounding may be permitted or prohibited, and feedback characteristics within the noise shaper can be modified to ensure that use 8-bit output is Yes DAC (as shown in Fig.6) or 10-bit DAC output (not shown) by use of suitable fields in the control field shaper noise for each interval, in the four registers RN16-RN46. The multiplexer MRH selects one of the four registers RN16-RN46 for each time interval, and the information obtained is re-synchronized by the register 630 and outputted to the control input filter noise shaper 632.
7, DDF - Digital modulation frequencies
The exact value of the inverter for any of the transmission channels is generated according to the principle of "interval for interval scheme DIF in block DDF modem (Figure 3), which is shown in detail in Fig.7. According to the principle of "interval for interval FIR filter transmission channel (not shown) generates a data stream complex (I, Q) of the information signal (16 kilosymbols/s)received from the modem DS, which will modulate each of the generated intermediate frequency. This stream of data can be formed in such a way that it can be transmitted in a limited frequency range allocated for the appropriate RF channel. Initial processing of the signal information includes the generation of pulses with finite impulse response to reduce the frequency range to +/-10 kHz. This conversion pulse generates in-phase and quadrature components for use in the modulation of the inverter.
After pulse shaping using multiple stages of linear interpolation. Initial interpolation is apolnet to increase the sampling frequency of the modulating signal, subsequent additional interpolation ultimately increase the sampling rate and increase the frequency at which appear the main spectral responses to 21,76 MHz. Suitable methods of interpolation are described, for example, in the book "Multirate Digital Signal Processing Crochiere and Rabiner, Prentice-Hall, 1993.
In-phase and quadrature components of the generated and interpolated baseband signal serves on the I and Q inputs of the mixers MH and MH modulatory circuit shown in Fig.7.
On the left side of figure 7 shows a diagram of the digital generation transmitted to the inverter. The exact generated by the inverter control when the base station informs the cluster controller CC (FIS), what number of intervals and the RF channel is assigned to time interval serving particular conversation. 24-bit number that identifies a specific inverter with high resolution (for example, +/-1,3 Hz), served processor DS/D (Figure 3) via data bus DS/D. This 24-bit reference frequency is recorded in a corresponding one of the 24-bit registers R17-R47. Each of the registers R17-R47 is intended for a specific one of the four TX time intervals.
The count of time intervals (not shown) generates a number of recurring case of double-bit time intervals obtained from the synchronization signal received via the backplane, the AK previously described. The signal readout time intervals takes place every 11,25 MS, regardless of whether you use this time interval for modulation DS, S or 16S. When the time interval at which it will be fixed this frequency is reached by the count of time intervals, the interval count selects the appropriate one of the registers R17-R47, using multiplexers MRH, to feed its contents to the register 702 resynchronization and ultimately to the upper input of the adder 704. Thus, another (or the same) of the inverter in the form of a 24-bit count can be used for each successive time interval. This 24-bit reference frequency is used as a phase jump for the usual schema of the drive phase, containing the adder 704 and register 706. Integrated carrier is generated by converting the accumulated phase information sawtooth register 706 sine and cosine signals using the scheme cosine approximation 708 and schemes sinusoidal approximation 722. These circuits 708 and 722 are described in detail in U.S. patent No. 5008900. The output signals of the circuits 708 and 722 re-synchronized registers 710 and 724, respectively, and are fed to the mixer 712 and 714, respectively. The output signals of the mixers 712 and 714 are served on the resynchronization registers 714 is 728, respectively. Mixers 712 and 714, together with the adder 716 form a normal complex (I, Q) modulator. The output signal of adder 716 combined with the cosine of the reference inverter multiplexer 718, which is controlled by a signalfrom an internal register (not shown) scheme DDF RSI 450 (Fig 3). The output signal of multiplexer 718 re-synchronized register 720, the output of which is connected to the noise shaper with variable coefficients, such as described with reference to Fig.6, consisting of the adder 734 and filter 732, with their associated control registers RN17-RN47, the multiplexer control MRH and Retiming registers 730 and 736.
The noise shaper compensate for quantization noise due to the finite resolution (illustrative, +/- half least significant bit) digital to analog conversions. Since the quantization noise is uniformly distributed, their spectral characteristics, apparently, similar to white Gaussian noise. Noise power, which falls within the bandwidth of the transmitted signal, which is relatively narrow compared to the sampling rate may be reduced in the same ratio in which the desired bandwidth refers to the frequency of sampling. For example, if the modulating signal has a bandwidth of 20 kHz, and the sampling rate is 20 MHz, the improvement of the signal-to-noise ratio which would be 1000:1, or 60 dB. Characteristics of the noise shaper is governed by the principle of "interval for interval 7-bit field control shaper noise, as described in connection with 6.
Fig - Generation sync system
An important aspect of our invention is that the speech quality is maintained, despite the physical separation of the base station and the remote cluster. Changes in bronirovanii between the base station and the cluster, as well as changes in bronirovanii when decoding and encoding of speech signals will lead to various forms of degradation of speech, who listens in the form of extraneous clicks and Petrucciani in the speech signal. According to the invention strict congruence of bronirovania guaranteed synchronization of all signals bronirovania, in particular signals used to synchronize the ADC, speech codecs modules 101-108 chetvertnyh lines and paths PCM 200 and 500, relative to the direct channel, As shown in Fig, the basic clock used in the system, is obtained by using a frequency generator 21,76 MHz (not shown), which gives a signal as shown on the left side Fig. This signal frequency 21,76 MHz is used for synchronization of the synchronizer samples with a frequency of 64 kHz with time character of the transition in renameman the radio signal. More specifically, the signal frequency 21,76 MHz first divided by 6.8 by using the schema of the fractional frequency divider synchronizer 802, which performs this fractional division by dividing the clock 21,76 MHz on 5 different factors in a repeating sequence 6, 8, 6, 8, 6 for receiving the clock with an average frequency of 3.2 MHz.
Programmable dividing device synchronizer 806 is a separating device of conventional type and is used to divide the clock of 3.2 MHz using a divider, the exact value of which is determined DS/D. Typically, programmable dividing device synchronizer 806 uses the divider 50 for receiving the synchronization signal sampling frequency of 64 kHz at its output. The output signal of the synchronizer sampling frequency of 64 kHz separating device 806 is used to gate the ADC 804 receiving channel (also shown in Figure 3). ADC 804 converts the received sampling the if signal to digital form for use by the processor DS/MDM.
On Fig processor DS/MDM acts as a phase/frequency comparator for calculating a phase error in the received symbols from their ideal phase value using the clock signal frequency 64 kHz to determine when measured phase error. The DSP/MDV determines the output signal of the fractional correction khromirovanym src="https://img.russianpatents.com/811/8110509-s.gif" height="5" width="5" > . It is served in a programmable dividing device 806 to determine the division factor. If the clock signal frequency of 64 kHz is a frequency slightly exceeding the frequency of the outcomes phase of the symbols in the received signal to the intermediate frequency, the processor DS/D gives the fractional correction bronirovania, which temporarily increases the divider separating device 806, extending thus the phase and lowering the center frequency of the output clock signal frequency 64 kHz separating device 806. Similarly, if the clock frequency of 64 kHz is lower than the frequency of the phase transitions of the received symbols, the divider separating device 806 transient decreases.
The clock signal of the sampling frequency of 64 kHz at the output of programmable divider clock device 806 is multiplied by the frequency multiplier 64 using conventional analog multiplier phase automatic frequency 808 for receiving the clock frequency of 4,096 MHz. Dot clock frequency 4,096 MHz is delivered to the switches time slots 310 and 320 (see Fig 1), which divides the synchronization signal 4,096 MHz at 2, forming two clock by 2,048 MHz, which are used speech codecs linear modules 101-108 (1) to sample and convert the analog speech input signal in the KM speech signals. The security is usually received sync pulse 2,048 MHz for volodkov, which is in synchronism with radio-generated sampling clock of 64 kHz, ensures that there will be slippage cycles between the two signals. As mentioned, such slippage otherwise would lead to a noticeable deterioration of the voice quality perceived as clicks and crackles in the speech signal.
The foregoing describes illustrative variant of the invention. Other options can be created by specialists in this field without departing from the essence and scope of the invention. Among these variants, for example, would increase the speed of the sample on the PCM buses for creating processing capabilities as PCM speech and transmitted signals on the same switch time intervals without compromising quality PCM speech coding. In addition, the pattern of formation of transmitted pulses SI (specialized IP) can be modified to ensure the application forms of modulation other than QPSK modulation, such as quadrature amplitude modulation and frequency modulation. It should be borne in mind that although the illustrative option describes the application of the General pool of modems with fast frequency agility to service a group of remote subscriber points in a modular cluster, similar to the group m is demov with fast frequency can be applied at the base station to service the connection between this cluster and any number of remote subscriber stations. Finally, can be used by different transmitting medium than radio, such as coaxial transmission line or the transmission line using the optical fiber cable.
1. Radiotelephone system containing a base station and multiple subscriber stations in remote modular cluster, in which the repeating group of time intervals supports communication between subscriber stations and the base station, characterized in that it contains
a group of modems (400), each modem is connected with the possibility of a direct digital synthesis of any of the many frequencies that identifies the channel into sequential time intervals,
cluster controller (300) for providing any of these modems to support communication between the subscriber stations and the base station in successive time intervals, and the cluster controller (300) includes a means for synchronization modems with the base station and
this provided the modem is configured to provide synchronization information of the other modems.
2. Radiotelephone system according to claim 1, characterized in that the specified cluster controller (300) provides modems in successive time intervals simultaneously at different frequencies, identifying the channel.
4. Radiotelephone system according to claim 3, characterized in that the other modems are in a state of reduced power to distribution of the time interval specified cluster controller (300).
5. Radiotelephone system according to claim 1, characterized in that the cluster controller (300) includes a means for serial transmission of commands specific to the modem from a variety of modems on searching among the frequencies that identifies a channel within one of the time intervals.
6. Radiotelephone system according to claim 1, characterized in that certain modems (400) calculates a corresponding set of synchronization parameters, and the cluster controller (300) determines the reliability of the corresponding sets of parameters synchronization and identifies one of the modems to deliver timing information to other modems.
7. Radiotelephone system according to claim 2, characterized in that it further comprises a Converter (600) to transform with increasing frequency, multiple frequencies, identifying the channel in the radio frequency range.
8. Radiotelephone system is about to claim 2, characterized in that it further comprises a Converter (600) for conversion with decreasing frequency range signals of the radio frequency received from the base station in the set of intermediate frequencies, identifying the channel.
9. Radiotelephone system according to claim 1, characterized in that the base station is the Central telephone base station.
10. Radiotelephone system according to claim 1, characterized in that the said group of modems (400) and cluster controller (300) is located in the cluster subscriber stations.
11. Radiotelephone system according to claim 1, characterized in that the said group of modems (400) and cluster controller (300) is located in the base station.
12. The method of minimization of synchronization delays and power consumption in the cluster subscriber line circuits served by many modems have access to any of the many frequencies that identifies a channel within a group of recurring time intervals, namely, that
A. synchronize the first of these modems with one time interval from a specified group of intervals,
B. distribute from the specified first modem to the rest of the modems synchronize with the specified one time interval and
C. divide the frequency that identifies the channel group of time intervals, the use of which has been created the first of these modems, before distribution of the time interval any of the other modems from multiple modems.
FIELD: data organization and control in cellular communication networks.
SUBSTANCE: proposed method includes generation of SMS message in the form of sequentially disposed data blocks starting from pointer block followed by generation of main data block, generation of first next data block with floating point numbers including compression operator, number operator, and floating-point representation, generation of next data blocks indicating only compression operator and mantissa whose value for this compression is found from expression M(l
EFFECT: elimination of other-than-data bits from message being transferred.
2 cl, 2 dwg
FIELD: radio communications engineering; digital communications in computer-aided ground-to-air data exchange systems.
SUBSTANCE: proposed system designed to transfer information about all received messages irrespective of their priority from mobile objects to information user has newly introduced message processing unit, group of m modems, (m + 1) and (m + 2) modems, address switching unit, reception disabling unit whose input functions as high-frequency input of station and output is connected to receiver input; control input of reception disabling unit is connected to output of TRANSMIT signal shaping unit; first input/output of message processing unit is connected through series-connected (m + 2) and (m + 1) modems and address switching unit to output of control unit; output of address switching unit is connected to input of transmission signal storage unit; t outputs of message processing unit function through t respective modems as low-frequency outputs of station; initialization of priority setting and control units, message processing unit clock generator, and system loading counter is effected by transferring CLEAR signal to respective inputs.
EFFECT: enhanced efficiency due to enhanced throughput capacity of system.
1 cl, 2 dwg