Patent Abstract:
The present invention reduces power consumption and costs for components, and improves acknowledgement speed by using a memory or the like used only for acknowledgement. A time-division multiple access radio communication device of the present invention includes a receive-data buffer portion for storing received data; a unique word detecting portion for detecting a unique word from the received data; a timer portion for counting time from the point at which the unique word is detected at the unique word detecting portion; a cyclic redundancy check (CRC) calculating portion for checking errors in the received data; and a send-data buffer portion for storing data to be sent. The time-division multiple access radio communication device is further provided with an acknowledgement data generating portion. The acknowledgement data generating portion checks errors in the received data based on the calculation effects at the CRC calculating portion in accordance with the timing counted at the timer portion, and when the received data are assumed to be error-free, the acknowledgement data generating portion automatically generates acknowledgement data, and stores the data in a storage region distinguished from the send-data buffer portion.

Full Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a time-division multiple access (TDMA) radio communication device that automatically can generate acknowledgement data and send the data for response. The present invention relates also to a time-division multiple access radio communication system using the device. 
     2. Description of the Prior Art 
     In recent years, various portable communication devices using time-division multiple access radio communication system have been developed. For the portability and durability, the devices are required to be smaller and to minimize power consumption. 
     An acknowledgement method for a conventional time-division multiple access radio communication system includes the following steps of: 
     storing received data in a receive-data buffer, based on a synchronization information at a unique word detecting portion; 
     carrying out CRC calculation by processing with software using a microprocessor; and 
     writing the results in a send-data buffer for sending. 
     An acknowledgement method in such a conventional time-division multiple access radio communication system is described below by referring to FIG.  4 . In FIG. 4, numeral  401  denotes an antenna for receiving data, and  402  denotes a unique word detecting portion. Numeral  403  denotes a receive-data buffer portion,  404  denotes a microprocessor portion, and  405  denotes a send-data buffer portion. Numeral  406  denotes an antenna for sending data,  411  denotes a receive-data processing path,  412  denotes a unique word detection signal, and  413  denotes a send-data processing path. 
     In FIG. 4, received data inputted from the antenna  401  is passed over the receive-data processing path  411  into the unique word detecting portion  402  and also the receive-data buffer portion  403 . When the unique word detecting portion  402  detects a unique word in the received data, it gives out the unique word detection signal  412  and notifies the microprocessor portion  404 . 
     In the microprocessor portion  404 , the unique word detection signal  412  is inputted and waits for a certain period until the received data are completely stored in the receive-data buffer portion  403 , so that the timing to start the cyclic redundancy check (CRC) calculation is adjusted. A remainder term as a result of division for checking transmission errors is added to the received data. 
     When the received data are completely stored in the receive-data buffer portion  403 , CRC calculation is carried out for obtaining the remainder term by the above-mentioned division based on the received data. If the remainder term obtained by the CRC calculation coincides with a remainder term (CRC) sent together with the received data, the received data are regarded as error-free, and acknowledgement send data are prepared in the send-data buffer portion  405  for acknowledgement. And the microprocessor portion  404  directs sending in accordance with timing of sending data at the certain station. Consequently, acknowledgement data are sent to the antenna  406  through the send-data processing path  413 , and the data are outputted as a radio wave. 
     However, in some time-division multiple access radio communication systems, acknowledgement should be sent immediately in accordance with the timing of the desired station. In such a case, a CPU is kept busy with the acknowledgement process or the CPU is unduly loaded if acknowledgment is carried out by the conventional software processing. And thus, it prevents other processes from being carried out on the CPU. To solve such a problem, acknowledgement is often processed with a high-speed microprocessor specialized for an acknowledgement process. However, it will cause some problems, e.g., the communication device consumes much power, or the component cost rises. 
     Such a conventional system uses a send-data buffer designed for normal communication. Therefore, the normal send-data should be moved to and kept in another memory during acknowledgement. This also causes problems, for example, the component cost rises and communication response deteriorates due to replacement of data. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to solve these problems by using memories or the like exclusive to acknowledgement, so that power consumption is lowered, component cost is reduced and speed of response is improved. 
     In order to achieve the object, a time-division multiple access radio communication device according to this invention comprises: 
     a receive-data buffer portion to receive data from plural sources by sing a carrier wave and store the received data; 
     a unique word detecting portion to detect a unique word from the received data to determine a synchronous point as a starting point for timing adjustment; 
     a timer portion for the timing adjustment by counting time from the point that the unique word is detected at the unique word detecting portion; 
     a CRC calculating portion to check errors in the received data; and 
     a send-data buffer portion to store the data to be sent. The time-division multiple access radio communication device is further provided with an acknowledgement data generating portion. This acknowledgement data generating portion checks errors in the received data based on a calculation result at the CRC calculating portion in accordance with the timing counted at the timer portion. When the received data are assumed to be error-free, the acknowledgement data generating portion generates acknowledgement data and stores the data in a storage region distinguished from the send-data buffer portion. 
     As a result, acknowledgement data can be sent without providing a high-speed microprocessor exclusive to acknowledgement. In addition, since the acknowledgement data are stored in a storage region distinguished from the send-data buffer portion, the acknowledgement data are not replaced by normal send-data at a send-data buffer. Thus, deterioration of the communication response can be prevented. 
     The time-division multiple access radio communication device preferably includes plural receive-data buffers at a receive-data buffer portion, and includes plural send-data buffers at a send-data buffer portion. If the device includes plural data buffers for receiving and sending data respectively, send-/receive-data are not replaced at the send-/receive-data buffers even when plural data are sent/received simultaneously, and consequently, deterioration of the communication response can be prevented. 
     A time-division multiple access radio communication method according to the present invention includes the following steps of: 
     receiving data from plural sources by using a carrier wave and storing the data; 
     detecting a unique word from the received data in order to determine a synchronous point as a starting point for timing adjustment; 
     counting time from the point that the unique word is detected; 
     carrying out CRC calculation for checking errors in the received data; and 
     storing the data to be sent. The method further includes the steps of: 
     checking errors in the received data based on the CRC calculation result; 
     generating acknowledgement data when the received data are assumed to be error-free; and 
     storing the acknowledgement data in a storage region distinguished from the send-data buffer portion. 
     As a result, acknowledgement data can be sent without providing a high-speed microprocessor exclusive to acknowledgment. In addition, since the acknowledgement data are stored in a storage region distinguished from the send-data buffer portion, the acknowledgement data are not replaced by normal send-data at a send-data buffer. And thus, deterioration of the communication response can be prevented. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram illustrating a time-division multiple access radio communication device according to a first embodiment of the present invention. 
     FIG. 2 is a block diagram illustrating a time-division multiple access radio communication device according to a second embodiment of the present invention. 
     FIG. 3 is a conceptual view illustrating mobile unit communication according to an embodiment of the present invention. 
     FIG. 4 is a block diagram illustrating a time-division multiple access radio communication device according to the prior art. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Embodiment 
     A time-division multiple access radio communication device according to a first embodiment of the present invention is described below with a reference to FIG.  1 . FIG. 1 is a block diagram illustrating a time-division multiple access radio communication device according to this embodiment. In FIG. 1, numeral  101  denotes an antenna for receiving data,  102  denotes a unique word detecting portion,  103  denotes a receive-data buffer portion,  104  denotes a CRC calculating portion,  105  denotes a timer portion,  106  denotes an acknowledgement data generating portion,  107  denotes a send-data buffer portion,  108  denotes an antenna for sending data,  111  denotes a receive-data processing path,  112  denotes a unique word detection timing signal,  113  denotes a CRC calculation timing signal,  114  denotes a CRC matching signal,  115  denotes an acknowledgement send timing signal, and  116  denotes a send-data processing path. The unique word detecting portion  102  can be composed of, for example, a serial register storing a unique word and a comparator. For the antennas  101  and  108 , an integrated antenna with a switch for send/receive can be used. However, there is no particular limitation to their configurations, and other configurations are possible as long as they provide equivalent functions. 
     A signal received at the antenna  101  is passed over the receive-data processing path  111  into the unique word detecting portion  102 , the receive-data buffer portion  103 , the CRC calculating portion  104  and the timer portion  105  respectively. 
     When the unique word detecting portion  102  detects a unique word from the received data, it gives out a unique word detection timing signal  112 , and notifies the timer portion  105  of the signal as a synchronous point. The timer portion  105  generates an accurate clock based on the received synchronous point in order to notify of a CRC calculation timing, send-data path switching timing, and acknowledgement send timing. All basic timings are counted at a clock synchronized with the received unique word detection timing signal  112 . 
     In a measurement of the CRC calculation timing, the timer portion  105  outputs the CRC calculation timing signal  113  in the CRC calculating portion  104  when data subjected to CRC calculation are completely received, according to a clock based on a point of time that the unique word detection timing signal  112  is inputted. 
     In a switching of the send-data path and measurement of the acknowledgement send timing, the acknowledgement send timing signal  115  is outputted at the time when the acknowledgement data are completely generated, according to a clock based on a point of time that the unique word detection timing signal  112  is inputted. 
     At the CRC calculating portion  104 , the received data are subjected to CRC calculation. A remainder term as a result of division for checking transmission errors is provided to the received data. When storage of the received data in the receive-data buffer portion  103  is completed, i.e., at the time when the CRC calculation timing signal  113  is notified, CRC calculation is carried out by conducting a similar division based on the received data for obtaining a remainder term. If the remainder term as a result of the CRC calculation and a remainder term (CRC) sent with the received data are coincided with each other, the CRC calculating portion  104  regards the received data as being free of burst errors, and outputs CRC matching signal  114  so as to notify the acknowledgement data generating portion  106  that no errors have been found in the received data. 
     When the CRC matching signal  114  is inputted in the acknowledgement data generating portion  106 , data for acknowledgement are generated inside the acknowledgement data processing portion  106 . When the acknowledgement send timing signal  115  generated at the timer portion  105  is inputted, the acknowledgement data generated at the acknowledgement data generating portion  106  is outputted to the send-data processing path  116  and sent from the antenna  108 . Data switching with normal send-data is carried out by the acknowledgement send timing signal  115  generated at the timer portion  105 . The connection from a normal send-data buffer portion  107  in the send-data processing path  116  is switched to the acknowledgement data generating portion  106 . 
     As described above, this embodiment automatically carries out generation of the timing signal from the time of detection of the unique word to acknowledgement, and also generation of acknowledgement data based on the CRC calculation results. Therefore, a calculation process by a high-speed microprocessor exclusive to acknowledgement is not needed, unlike conventional acknowledgement processes using software. As a result, plural microprocessors are not necessary, and the microprocessor is not required to have high performance. Therefore, the components can be reduced and the power consumption can be lowered. 
     Moreover, normal send-data can be stored in the send-data buffer portion, as the acknowledgement signal is generated at the acknowledgement data generating portion. And thus, replacement of the acknowledgement data with normal data is not necessary. As a result, periods for data replacement is reduced and response for send/receive can be improved. In addition to that, since memories or the like for replacement are not needed, components for the device can be reduced and power consumption is also lowered. 
     Second Embodiment 
     A time-division multiple access radio communication device according to a second embodiment of the present invention is described below with reference to FIG.  2 . FIG. 2 is a block diagram illustrating a time-division multiple access radio communication device according to this embodiment. In FIG. 2, numeral  201  denotes an antenna for receiving data,  202  denotes a unique word detecting portion,  203  denotes a receive-data buffer portion composed of plural receive-data buffers for respective time-division multiple access radio communications,  204  denotes a CRC calculating portion,  205  denotes a timer portion,  206  denotes an acknowledgement data generating portion,  207  denotes a send-data buffer portion composed of plural send-data buffers for respective time-division multiple access radio communications,  208  denotes an antenna for sending data,  211  denotes a receive-data processing path,  212  denotes a unique word detection timing signal,  213  denotes a CRC calculation timing signal,  214  denotes a CRC matching signal,  215  denotes an acknowledgement send timing signal, and  216  denotes a send-data processing path. The unique word detecting portion  202  can be composed of, for example, a serial register storing a unique word and a comparator. For the antennas  201  and  208 , an integrated antenna with a switch for send/receive can be used. However, there is no particular limitation to their configurations, and other configurations are possible as long as they provide equivalent functions. 
     A signal received at the antenna  201  is passed over the receive-data processing path  211  into the unique word detecting portion  202 , the receive-data buffer portions  203 , the CRC calculating portion  204  and the timer portion  205  respectively. 
     When the unique word detecting portion  202  detects a unique word from the received data, it gives out the unique word detection timing signal  212 , and notifies the timer portion  205  of the signal as a synchronous point. The timer portion  205  generates an accurate clock based on the received synchronous point in order to notify a CRC calculation timing, send-data path switching timing, and acknowledgement send timing. All basic timings are counted at a clock synchronized with the received unique word detection timing signal  212 . 
     In a measurement of the CRC calculation timing, the CRC calculation timing signal  213  is outputted at the time when data subjected to CRC calculation are completely received, according to a clock based on a point of time that the unique word detection timing signal  212  is inputted in the CRC calculating portion  204 . 
     In a switching of the send-data path and measurement of the acknowledgement send timing, the acknowledgement send timing signal  215  is outputted at the time when the acknowledgement data are completely generated, according to a clock based on a point of time that the unique word detection timing signal  212  is inputted. 
     At the CRC calculating portion  204 , the received data are subjected to CRC calculation. A remainder term as a result of division for checking transmission errors is provided to the received data. When storage of the received data in the receive-data buffer portions  203  is completed, i.e., at the time when the CRC calculation timing signal  213  is notified, CRC calculation is carried out by conducting a similar division based on the received data for obtaining a remainder term. If the remainder term as a result of the CRC calculation and a remainder term (CRC) sent with the received data are coincided with each other, the CRC calculating portion  204  regards the received data as being free of burst errors, and outputs CRC matching signal  214  so as to notify the acknowledgement data generating portion  206  that no errors have been found in the received data. 
     When the CRC matching signal  214  is inputted in the acknowledgement data generating portion  206 , data for acknowledgement are generated inside the acknowledgement data processing portion  206 . When the acknowledgement send timing signal  215  generated at the timer portion  205  is inputted, the acknowledgement data generated at the acknowledgement data generating portion  206  is outputted to the send-data processing path  216  and sent from the antenna  208 . Data switching with normal send-data is carried out by the acknowledgement send timing signal  215  generated at the timer portion  205 . The connection from a normal send-data buffer portions  207  in the send-data processing path  216  is switched to the acknowledgement data generating portion  206 . 
     In this embodiment, plural receive-data buffer portion  203  and send-data buffer portion  207  are provided with plural buffers respectively for plural time-division multiple access radio communications. Therefore, data concerning respective opponent communicators are stored in the respective receive-data buffers  203  and the respective send-data buffers  207 . Even when plural time-division multiple access radio communications are carried out simultaneously, received data are stored in each buffer for each communicator, and the data are not replaced among the buffers. As a result, the communication response can be kept. 
     In this embodiment, effects equivalent to the first embodiment are expected. In addition, even when plural time-division multiple access radio communications are carried out simultaneously, the received data are stored in the respective buffers and the data are not replaced among the buffers. So the response for send/receive can be kept. 
     A time-division multiple access radio communication device in one embodiment of the present invention is described below. FIG. 3 is a conceptual view illustrating application of a time-division multiple access radio communication device of this embodiment to a mobile unit communication system. In FIG. 3, numeral  301  denotes a mobile unit communication terminal (e.g., an automobile station),  302  denotes a mobile unit communication base station. Numeral  303  denotes an area covered by a base station, and  304  denotes a service area. 
     In a general mobile unit communication system, the communication is subject to considerable interfering waves, depending on the locations of the mobile unit communication terminal  301  and the mobile unit communication base station  302 . In order to reserve stable communication in such a case, the whole service area  304  should be enlarged either by enlarging the area  303  that a mobile unit communication base station  302  covers, or by increasing the number of the mobile unit communication base stations  302 . 
     However, in order to enlarge the area  303  that a base station  302  covers, the transmission output of the mobile unit communication base station  302  and of the mobile unit communication terminal  301  should be increased. This requires a comparatively large-scaled remodel for the mobile unit communication base station  302 , and service will be suspended for a certain period. In addition, output of the mobile unit communication terminal  301  cannot be increased easily since the capacity and weight are restricted to keep its portability. Therefore, increase of output is not a proper method. 
     When a time-division multiple access radio communication device of the present invention is used for the mobile unit communication base station  302 , the relay device of a base station can be small and light-weight as the components will be decreased. As a result, the numbers of the mobile unit communication base stations  302  can be increased readily, and the service area  304  can be enlarged. 
     Similarly, the weight of the mobile unit communication terminal  301  can be reduced by using a time-division multiple access radio communication device of the present invention, since the components will be reduced. Moreover, since such a device consumes less power, the capacity of the battery can be made smaller to reduce the weight of the mobile unit communication terminal  301 . Since less power is consumed, the operating time can be extended, and portability of the mobile unit communication terminal  301  is improved. 
     The above effects will not be limited to this embodiment but similar effects can be expected for small area communication represented by PHS. The present invention is effective also for improvement of the communication response. 
     According to the time-division multiple access radio communication device of the present invention and the method using the same, generation of the timing signal from detection of the unique word to acknowledgement, and also generation of acknowledgement data based on the CRC calculation results, are carried out automatically. Therefore, a calculation process by a high-speed microprocessor exclusive to acknowledgement is not needed unlike conventional acknowledgement processes using software. As a result, plural microprocessors are not necessary, and the microprocessor is not required to have high quality. Therefore, the components for a device can be reduced and the power consumption can be lowered. 
     Moreover, normal send-data can be stored in the send-data buffer portion, as the acknowledgement signal is generated at the acknowledgement data generating portion. And thus, replacement of the acknowledgement data with normal data is not necessary. As a result, the time for data replacement is reduced and response of send/receive can be improved. In addition to that, as memories or the like for replacement are not needed, the components for the device can be reduced and power consumption is also lowered. 
     The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The embodiments disclosed in this application are to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Technology Classification (CPC): 8