JPH06252841A - Message extract device for cellular telephone reception section - Google Patents

Abstract

PURPOSE:To relieve the load on a microprocessor by providing a message extract circuit comprising a hardware and giving its command only by the microprocessor. CONSTITUTION:An input signal is inputted to a data word extract section 1-4-2 and a shift register 1-4-5. On the other hand, a microprocessor 1-6 designates a DSAT color code by a signal DM and a DSAT pattern generator 1-4-3 outputs a corresponding DSAT pattern. Moreover, the processor 1-6 sets a permissible error bit number to signals PM1, PM2 at scan search and shift search. A DSAT part of the data inputted to a shift register is compared with a DSAT pattern from a generating section 1-4-3 to check whether or not a range of an allowable error exceeds the value set in the signal PM1. A synchronization word is detected by a synchronization word detection section 1-4-4 and it is used to trigger for data word extraction. The extract section 1-4-2 regards a predetermined bit after synchronization word detection as a data bit and samples only an even numbered bit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to telephone communication such as a cellular system, in which a mobile station is transmitted from a base station to a mobile station when the mobile station communicates with the base station via a radio link via a telephone line. The present invention relates to a message extracting device of a cellular telephone receiving unit for extracting a message to be used.

[0002]

2. Description of the Related Art AMPS (Advanced Mobil) is generally used as a mobile telephone service system in which a cellular telephone device is used.
Phone Service) and TACS (Total Access Community)
application system), and NAMPS and NTACS having low-frequency data are known. This is communicated wirelessly between a base station and a mobile station established in an area of appropriate size, the mobile station digitally processing all data and control information to be communicated, and a microprocessor. It is common to provide internal control information to a set of mobile stations by means of a logical unit configured by, and the required function is often realized by software.

In the above mobile telephone service system, there may be a plurality of mobile stations in the radio area of one base station, so that different mobile stations may transmit at the same time and compete with each other. The base station uses a control channel to communicate digital control information with the mobile station to control the mobile stations within the radio wave area, and to prevent the competition between them to perform normal communication. Therefore, Air Spec
Is provided and it is determined accordingly whether or not the current communication is normal.

Further, in the above-mentioned Air Spec, as shown in FIG. 2, the format of the downlink communication channel message stream from the base station to the mobile station is determined. In the figure, a 30-bit bit string called a synchronization word is transmitted at an NRZ of 200 bits / sec so that the mobile station can synchronize with the incoming data. Each data word is sent as Manchester coded data of 100 bits / second and is composed of 40 bits including parity. The leftmost bit is treated as the most significant bit, and the upper 28 bits in the 40-bit field are information bits. When there is no information, the DSAT of a specific color code (described later) is always used.
(Digital monitoring audio tone) A pattern sequence is repeatedly sent continuously. When the information is present, the synchronization word + data word is sent in such a manner that it interrupts the preceding continuous DSAT pattern sequence. Conventionally, the extraction processing of these messages is all processed by the microprocessor.

[0005]

However, in the prior art, the identification of the DSAT pattern from the input signal, the detection of the synchronization word, and the extraction of the data word were all handled by software, so a high speed microprocessor. However, there is a problem in that the cost is increased, the required memory capacity and the power consumption are also increased.

The present invention has been made in view of the above points, and in order to eliminate the above-mentioned problems, the above-mentioned message extraction circuit is provided by hardware, and the microprocessor gives only the command to the microprocessor. An object of the present invention is to provide a message extracting device for a cellular telephone receiving unit that reduces the load on the processor.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a cellular phone of a mobile station which communicates wirelessly with a base station.
In the message extracting device of the telephone receiving section, as shown in FIG. 1, the mobile station 1 is provided with a shift clock control section 1-4-1,
Data word extracting section 1-4-2, DSAT pattern generating section 1-4-3, synchronous word detecting section 1-4-4, shift register 1-4-5, DSAT detecting section 1-4-4- 6, DSA
A message extractor composed of a T scan register 1-4-7 and a DSAT error count unit 1-4-8 is provided.
The microprocessor 1-6 is characterized by specifying a DSAT pattern from an input signal, detecting a synchronization word, and extracting a data word.

[0008]

In the present invention, since the message extracting section 1-4 specifies the DSAT pattern from the input signal, detects the synchronization word, and extracts the data word, it is dedicated hardware. The microprocessor 1-6 may set the allowable number of error bits and process the extracted data.
This reduces the load on the microprocessors 1-6,
Since an inexpensive microprocessor can be used, the cost can be reduced, and the power consumption and size of the mobile station can be reduced. Further, by setting the allowable number of error bits arbitrarily, a stable detection rate can be secured even in a receiving state in various radio wave environments.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a message extracting device of a cellular telephone receiving unit according to the present invention. As shown, the cellular telephone system comprises a mobile station 1 and a base station 4.
, And communicates between them via radio waves via antennas 2 and 3. The mobile station 1 includes a high frequency amplification unit 1-1, a filter unit 1-2, a reception signal decoding unit 1-3 that decodes a reception signal,
Message extractor 1-4, BCH, which is the main part of the present invention
A decoder 1-5, a microprocessor 1-6 for processing signal data, and a transmission signal encoder 1-7. The message extraction unit 1-4 is a shift clock control unit 1-4-4-
1, data word extraction unit 1-4-2, DSAT pattern generation unit 1-4-3, synchronous word detection unit 1-4-4, shift register 1-4-5, DSAT detection unit 1- 4-6, D
SAT scan register 1-4-7 and DSAT error
It is composed of a counting unit 1-4-8.

FIG. 2 shows the format of the downlink communication channel message stream from the base station to the mobile station. Data is transmitted from the base station 4 according to the format shown in FIG. As described above, a 30-bit bit string called a synchronization word is transmitted at a NRZ of 200 bits / sec so that the mobile station can synchronize with the incoming data. The data word is sent as Manchester coded data of 100 bits / second and is composed of 40 bits including parity. The leftmost bit is treated as the most significant bit, and the 40-bit field is
The upper 28 bits in the field are information bits.

When there is no information, the DSAT shown in FIG.
Any one of the specific patterns in the color code DSAT pattern sequence is constantly and continuously sent. When the information is present, the synchronization word + data word is sent in such a manner that it interrupts the preceding continuous DSAT pattern sequence.

The above-mentioned data transmitted from the base station 4 is received by the antenna 2 of the mobile station 1, and the high frequency amplifier 1-1,
The data word is extracted by the message extracting section 1-4 through the filter section 1-2 and the received signal decoding section 1-3, and the BCH is extracted.
Microprocessor 1 decoded by the decoder 1-5
It is input to -6 and processed. The transmission from the mobile station 1 to the base station 4 is performed by the transmission signal encoding unit 1 from the microprocessor 1-6.
-7 encoded by the filter unit 1-2, high-frequency amplifier unit 1-
1, transmitted via the antenna 2.

The message extracting section 1- will be described below with reference to FIG.
The operation of No. 4 will be described. Input signal (RMD) is data
De-extractor 1-4-2 and shift register (30 bits)
Entered in. On the other hand, the microprocessor 1-6 outputs the signal D
Specify the DSAT color code (see Fig. 3) with N and DSA
The T pattern generator 1-4-3 outputs the corresponding DSAT pattern. The microprocessor 1-6 is a DSA
A signal PM1 is set to the number of allowable error bits in the first scan search (described later) of the T pattern, and a signal PM2 is set to the number of allowable error bits in the second and subsequent shift searches (described later) of the DSAT pattern. The signal CP5 is a transfer clock (200 Hz) for transferring the input signal RMD to the shift register 1-4-5, and the signal NCP is a system clock of 1.2 MHz used for the shift search.

In the case where the DSAT pattern shown in FIG. 3 is detected for some reason, the undetected state once occurs and the recovery is continued again, in order to promptly recover the detected state, the scan search mode and the shift search mode are selected. Can be used properly.
The switching is automatically performed by the shift clock controller 1-4-1. In the first scan search mode, the input signal RM
D is shifted to the 30-bit shift register 1-4-5 and DSA is input during 5 ms when the next bit data is input.
The T pattern is detected as follows.

The 24-bit DSAT portion of the data (RMD) input to the shift register 1-4-5 is a DSAT.
The comparison DSAT pattern input from the pattern generation unit 1-4-3 via the DSAT scan register 1-4-7 and the DSAT detection unit 1-4-6 are compared on a bit-by-bit basis. DSAT error counting section 1-4
8 is output. DSAT error counting section 1-4-8
Then, the number of unmatched error bits is counted, and the total number of bits is returned to the shift clock controller 1-4-1. If the shift clock controller 1-4-1 exceeds the allowable error number range set by the signal PM1, the shift clock controller 1-4-1 bit-rotates the DSAT scan register 1-4-7 to D
The SAT pattern is shifted by 1 bit, and it is again checked whether the allowable error number range is exceeded. If the allowable error number is exceeded even after rotating 23 times, the scan search mode is stopped and the extra power is not consumed until the next input signal RMD is shifted.

If the error bit number falls within the range of the allowable error number in the middle of the scan search mode, the scan search mode ends there, and the same speed 5 ms after the next shift of the input signal RMD. Move to shift search mode.

If an error occurs during the shift search mode, it returns to the scan search mode again. Further, when the number of allowable error bits is set to the scan search mode, the value set by the signal PM1 is set. When the shift search mode is set, the signal PM2 is set.
Can be set independently to the value set in.

FIG. 4 is a diagram showing an example of a synchronization word pattern. As shown in the figure, the synchronization word consists of 30 bits, and its detection is performed by the synchronization word detection unit 1-4-4. This detection triggers the extraction of data words, and it is not a good idea to make it unnecessarily severe due to the influence of the radio wave environment. Therefore, in order to have a certain degree of allowance, it is not necessary to check all bit matches for each bit, but to set 30 bits to 4
If it is divided into blocks and one of them is in agreement, the synchronization word is detected. The method will be described below.

The first block is a 30-bit synchronization word.
Block that takes out the odd-numbered bit of the code, the second block takes out the even-numbered bit of the 30-bit sync word, and the third block takes out the 30-bit sync word. The first half 1 to 13 bits take out odd-numbered bits, the second half 16 to 30 bits take out even-numbered bits, and the fourth block takes 2 to 14 in the first half out of 30-bit sync words. Bits take out even-numbered bits, and the latter half 15 to 29 bits form blocks in which odd-numbered bits are taken out. If even one of the blocks matches the synchronization word shown in FIG. 4, the synchronization is detected.

The data word is 40 bits of Manchester code (2 bits 01 represents 1 and 10 represents 0) following the synchronization word and is transmitted at 100 bps. The data word extracting unit 1-4-2 regards 80 bits after the detection of the synchronous word as data word, samples only the even number bits and outputs them to the BCH decoder 1-5.
The data word is decoded by the BCH decoder 1-5 and input to the microprocessor 1-6 for processing.

As described above, in this message extracting device, the data word extracting section 1-4 is used when no information arrives.
-2 is not operated, but is operated only when a synchronous word is detected, thereby reducing power consumption. Also, D
In the scan search mode in the SAT detection, after 24 bits have completed one cycle, the scan is stopped and the power consumption is reduced.
Further, during the data word extraction period, the DSAT detection operation is stopped to reduce the power consumption. The allowable number of error bits is independently set in the scan search mode and the shift search mode to cope with the radio wave environment.

[0022]

As described in detail above, according to the present invention, the following excellent effects are expected. (1) Since the message extractor uses dedicated hardware to specify the DSAT pattern from the input signal, detect the synchronization word, and extract the data word, the microprocessor sets the allowable number of error bits. It is only necessary to process the extracted data, which reduces the load on the microprocessor and allows the use of an inexpensive microprocessor, thus reducing the cost and reducing the power consumption and downsizing of the mobile station.

(2) Further, by setting the allowable number of error bits arbitrarily, a stable detection rate can be secured even in a receiving state in various radio wave environments.

(3) Since the above functions have been implemented as dedicated hardware, in the case of trouble, the problem becomes clear and the manufacturing and maintenance become easy.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a message extracting device of a cellular telephone receiving unit according to the present invention.

FIG. 2 is a diagram showing the format of a downlink communication channel message stream.

FIG. 3 is a diagram showing an example of a DSAT color code and a DSAT pattern.

FIG. 4 is a diagram showing an example of a pattern of a synchronization word.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mobile station 1-1 High frequency amplification part 1-2 Filter part 1-3 Received signal amplification part 1-4 Message extraction part 1-4-1 Shift clock control part 1-4-2 Data word extraction part 1-4-3 DSAT pattern generation section 1-4-4 Synchronous word detection section 1-4-5 Shift register 1-4-6 DSAT detection section 1-4-7 DSAT scan register 1-4-8 DSAT error -Counting unit 1-5 BCH decoder 1-6 Microprocessor 1-7 Transmission signal coding unit 2 antenna 3 antenna 4 base station

Claims (1)

[Claims] 1. A message extracting device for a cellular telephone receiving unit of a mobile station, which comprises a data processing microprocessor and wirelessly communicates with a base station, wherein the mobile station has a data word extracting unit. , DSA that generates DSAT pattern according to designation from microprocessor
A T-pattern generator, a DSAT detector, a DSAT scan register, a DSAT error count unit, a synchronous word detector, a shift register for storing input data, and a message extractor including a shift clock controller are provided. From the input signal to DS by the designation from the microprocessor
A message extracting device for a cellular telephone receiving unit, characterized in that an AT pattern is specified, a synchronization word is detected, and a data word is extracted.