JP2799945B2 - Mobile phone system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable telephone system which is a portable wireless digital telephone.

[0002]

2. Description of the Related Art In recent years, instead of analog cordless phones, PHP (Personal Handy Phone) has been used.
The development of a digital mobile phone system, called e), a second generation cordless phone, is underway. In such a cellular phone system, a digital system is adopted for communication between a mobile station called PS and a base station called CS, and analog signals such as voices are AD-converted or DA-converted into digital signals. It performs wireless communication.

FIG. 5 shows the configuration of such a portable telephone system, in which a base station 1 is connected via a subscriber line L, and the base station 1 and four mobile stations 21 to 24 are wirelessly connected. By the way, a 1.9 GHz band is used as a radio frequency band, and a carrier frequency interval is 300 KH.
z. Then, communication can be performed between one base station and four mobile stations via one frequency band. In this case, this frequency is time-divided into eight time slots to eight time slots within 5 msec as shown in FIG. The base station 1 transmits data to each mobile station in the first four time slots, and receives data from each mobile station in the remaining four time slots. As described above, since the same frequency can be used by four mobile stations, radio waves can be effectively used.

In such a case, as shown in FIG. 7, each mobile station is provided with a frame counter 231 for generating an address synchronized with the frame timing, and the address of the frame counter 231 is stored in each of the decoders 232A to 232.
H to generate a reception timing signal and a transmission timing signal for each time slot as shown in FIG. The decoded timing signals are input to a multiplexer (MUX) 233, which is a large-scale selection circuit, and the multiplexer 233 is connected to the CPU 34.
Controls various timing signals in slots required for data communication.

[0005]

In each of these mobile stations, slots may be moved at the time of link establishment or in accordance with an instruction from the base station in order to avoid mutual interference of radio waves.
Therefore, in the conventional mobile station, eight decoders 232A for generating various timing signals corresponding to each slot are provided.
232H are provided. However, each decoder has 2
Since it is a large-scale device equivalent to 000 to 5000 gates and a large-scale multiplexer is required, the circuit scale becomes large and it is difficult to reduce the size of the device, and the power consumption of the device is reduced. There were many disadvantages.

Accordingly, it is an object of the present invention to realize a mobile station that has a small size and low power consumption.

[0007]

SUMMARY OF THE INVENTION In order to solve such a problem, the present invention comprises a base station and a plurality of mobile stations, and a communication between the base station and the plurality of mobile stations at predetermined time slots. And a first counter for generating a frame address for each time slot by inputting a first clock indicating a communication speed per bit of data, and inputting the frame address. A decoder for generating transmission and reception timings, a clock generation circuit for receiving a first clock and generating a second clock corresponding to one time slot, and always generating a frame address of a first counter. A movement value is set based on a time slot movement request from the base station while permitting operation, and the movement value is counted based on the second clock. Are those provided a second counter for prohibiting frame address generation operation of the first counter in the mobile station.

[0008]

In the mobile station, the second counter always permits the frame address generation operation of the first counter, and the decoder generates transmission and reception timing signals. Here, when a base station requests a time slot movement and the movement value is set in the second counter, the movement value is counted by the second counter and the frame address generation operation is prohibited during this time. As a result, the time slot is moved. Therefore, when changing the time slot in the mobile station, it is not necessary to provide a decoder having a large circuit scale for each time slot, so that the mobile station can be made smaller and the power consumption can be reduced.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 3 is a block diagram of a mobile station constituting the mobile phone system of the present invention. In FIG. 1, the mobile station 2 is wirelessly connected to the base station 1 via a wireless unit including an antenna AT, a high frequency unit 21A, a wireless control unit 21C, and a wireless interface unit 21D.

Here, the wireless interface unit 21D includes:
Unique word detector 2 via timing bus TBS
2. Timing generation unit 23, reception CI inspection unit 24, scramble unit 25, CRC processing unit 26, reception data register 27, transmission data register 28, transmission data connection unit 2.
9, a simple confidentiality section 30, speed conversion sections 31 and 32, and a voice processing section 33 are connected.

The system bus SBS includes the above-mentioned reception CI checking unit 24, transmission data connection unit 29, and speed conversion unit 3
Each part except for 1 and 32 is connected, and the CPU 3
4. The operation unit 35 and the display unit 36 are connected. In addition,
A handset 37 and a ringer 38 necessary for a telephone call are connected to the voice processing unit 33.
It operates by the power supply from.

[0012] The mobile station 2 thus configured is connected to the base station 1.
When data communication is performed with the base station, data is received from the base station 1 via one of the eight time slots in which one frequency is divided every 5 msec. Then, data is transmitted to the base station 1 via a slot delayed by four slots from the reception slot. The time slot is 625 μsec (5 msec) per slot.
c / 8) is allocated and the data for one slot is 240 bits. Therefore, the data for one bit requires about 2.6 μsec. Therefore,
The speed of the transmitted and received data is 384 KHz.

FIG. 4 is a diagram showing a format of data transmitted to and received from the base station 1. As data, 224 bits of information are transmitted and received per slot. Here, from the 240-bit data for one slot,
The 16-bit data obtained by subtracting the 4-bit data is used as a guard time for preventing data (transmission burst signal) from colliding between two adjacent slots. A time slot is roughly divided into a control physical slot and a communication physical slot, and the control physical slot has a channel called SCCH. The SCCH channel is a channel for individual cells, and is a channel for transferring information necessary for call connection.
The communication physical slot has an information channel called TCH, a FACCH channel, and the like.
The CCH channel is a channel for temporarily transferring data by stealing the TCH channel.

As shown in FIG. 4A, the control physical slot has a 4-bit transient response ramp time R, a 2-bit start symbol SS, and a 62-bit preamble P.
R, 32-bit unique word UW, 4-bit type signal CI indicating the type of data, 42-bit destination identification code, 28-bit calling identification code, 34-bit control information I, and 16-bit error detection CRC ( Cyclic
Each data area of Redundancy Check is allocated.

As shown in FIG. 4 (b), the communication physical slots are 4
And a 2-bit ramp time R and a start symbol S
S is assigned, followed by a 6-bit preamble P
R, a 16-bit unique word UW is allocated. Subsequently, the 4-bit type signal CI, TCH
A 16-bit control channel SA, which is a channel associated with the channel, a 160-bit information I, and a 16-bit error detection CRC are allocated. FIG.
4A and FIG. 4B, data from the head to the unique word UW indicates synchronous data.

Next, the operation of the mobile station 2 for transmitting burst data in the above-described format will be briefly described with reference to FIGS. When a radio signal having a frequency of about 1.9 GHz is transmitted from the base station 1 to the mobile station 2, the radio signal including the antenna AT, the high-frequency unit 21A, the radio control unit 21C, and the radio interface unit 21D transmits the radio signal. High-frequency components are removed, demodulated, and output from the wireless interface unit 21D as reception data a having a frequency of 384 KHz.

The received data a is received by the unique word detecting section 22 and the received CI checking section 24. In each section, based on each reception timing output of the timing generating section 23, each unique word is selected from among the burst-shaped received data a. A type signal CI indicating a received data type such as a UW and a channel type is detected. The detected information is fed back to the timing generation unit 23, and is used to generate timing required for subsequent data reception. Then, the generated timing signal is transmitted to the timing bus TB.
The data is output to the transmission / reception processing units such as the scramble unit 25, the simple secret unit 33, and the voice processing unit 33 via S. in this case,
The scrambler 25 removes the scramble for maintaining the DC balance of the code string applied to the received data a and outputs it to the received data register 27.

In the CPU 34, these unique words U
Based on the reception timing output after detecting the W and the type signal CI, data such as a destination identification code, a calling identification code and information I stored in the reception data register 27 after the channel type CI are input via the system bus SBS. If these identification codes correspond to the own device, various protocol processing and received data processing are performed.

As described above, in the mobile station 2, when processing the reception data a, the unique word detection unit 22 and the reception CI
The inspection unit 24 detects the unique word UW and the type signal CI indicating the type of the received data, and based on these detections, generates the subsequent data reception timing, and generates a scramble unit 25, a CRC processing unit 26, and a reception data register 2.
7, transmission data register 28, transmission data linking unit 29,
The speed converters 31 and 32 are configured to operate without the CPU 34 interposed therebetween. As a result, the load on the CPU 34 is reduced, and
No. 4 can perform subsequent data processing with sufficient time, and since an accurate timing signal is generated according to the type of received data, there is no loss of a burst signal and efficient data reception. Processing can be performed.

When the received data a is the information I of the physical slot for communication and indicates a voice signal, the information is canceled in the simple privacy section 30 and
The signal is expanded into a signal of 32 KHz by the speed converter 31, converted into an analog signal by the audio processor 33, and output from the handset 37.

When the CPU 34 detects the transmission operation of the operation unit 35, it creates data based on the above-described format and outputs the data to the transmission data register 28. The transmission data register 28 transmits the transmission data based on each transmission timing from the timing generation unit 23 to the data connection unit 2.
9 to the CRC processing unit 26. The CRC processing unit 26 adds an error detection code to the transmission data and sends the transmission data to the scramble unit 25, and the scramble unit 25 applies a DC balance to the transmission data and sends it as transmission data b to a radio unit such as the radio interface unit 21D. Then, the radio section modulates the transmission data b and superimposes the modulated signal on a high frequency and transmits the radio signal to the base station 1 as a radio signal.

In this way, the calling protocol is executed between the base station 1 and the called terminal is called, and the call is started by the response from the called terminal. In this case, the audio signal from the transmitter / receiver 37 is converted into a digital signal having a frequency of 32 KHz by the audio processing unit 33, further compressed to a frequency of 382 KHz by the speed conversion unit 32, and transmitted to the simple secret unit 30. The simple confidential section 30 performs confidential control on the voice data, for example, taking an exclusive OR, and sends the voice data to the transmission data linking section 29. Thereafter, the voice data is transmitted to the partner terminal via the base station 1 via the above-described route.

In such a mobile station, data transmission / reception is performed using the time slots determined as described above. However, time slots may be moved at the time of link establishment or in accordance with an instruction from the base station in order to avoid mutual interference of radio waves. In such a case, in the present embodiment, the slot can be moved quickly by a simple circuit configuration.

FIG. 1 is a block diagram showing an embodiment of the portable telephone system according to the present invention, and shows a main part of a timing generation section 23 in the mobile station 2 when moving a time slot. In this case, the timing generation unit 23
Is a frequency dividing circuit 23 in addition to the frame counter (first counter) 231 and the decoder 232 shown in FIG.
4 (clock generation circuit), a down counter (second counter) 235, and an inverter 236.

In the mobile station 2, the reception data a and the transmission data b are received and transmitted by the clock signal of the frequency 384 KHz as described above, and one time slot has 240 bits. This frequency 384KHz
Is transmitted to the frame counter 231 and the frequency dividing circuit 234. When the frequency dividing circuit 234 receives the clock signal CK1 via the terminal CK, the clock pulse for one time slot (second
This is divided by 240 to generate a clock CK2. Then, the divided clock signal CK2 is output to the terminal CK of the down counter 235.

When the value of the down counter 235 is "0", a signal of "H" level is output from the output terminal OUT. Therefore, the frame counter 231 connected to the output terminal OUT outputs "H" level while the terminal CE is "H". Level, an address synchronized with the frame timing is generated from the input clock signal CK1 and the decoder 23
2 is output. Since the down counter 235 has its terminal CE connected to the “H” level output terminal OUT via the inverter 236, the level of the terminal CE is “L” during that time.
No counting operation is performed even if the clock pulse CK2 from 4 is input.

In such a situation, when, for example, “3” is given to the down counter 235 as data from the CPU 34 via the data bus DB in the system bus SBS, the down counter 235 counts down the data value “3”. To start. That is, in this case, since the value of the down counter 235 is not “0”, the output terminal OUT
Is at "L" level, and its terminal CE is at "H" level.
The countdown operation is performed in synchronization with the clock pulse CK2 from the frequency dividing circuit 234. The down counter 23
During the countdown operation of No. 5, the frame counter 231 connected to the output terminal OUT of low level and the terminal CE.
Does not operate even when the clock signal CK1 is input.

Thereafter, when the value of the down counter 235 becomes "0" as a result of the countdown, the frame counter 231 resumes its operation because the terminal CE becomes "H" level. Then, the clock signal CK1 is input to generate an address synchronized with the frame timing, and output to the decoder 232 to generate various timing signals.

FIG. 2 is a diagram showing signal waveforms of various parts of the mobile station 2 during the movement of time slots.
(D) shows the reception timing signals c and d and the transmission timing signals e and f output from the decoder 232. By the way, in the mobile station 2, if the reception timing signals c and d are output from the decoder 232 in the time slot [FIGS. As described above, the transmission timing signals e and f are output in the time slot four slots behind the slot.

When the base station 1 instructs the mobile station 2 to move, for example, for three slots, the decoder 232
Output the transmission timing signals e and f in a time slot three slots delayed from the original time slot [FIGS. 2C and 2D]. That is, in this case, the CPU 34
Outputs data “3” as a count value to the down counter 235 via the data bus DB [FIG.
(G)], an "H" level select signal h is output from the terminal SEL [FIG. 2 (f)]. As a result, the value of the down counter 235 is no longer "0", so that the output signal g of the terminal OUT becomes "L" level as described above [FIG. 2 (e)].

When the output of the down counter 235 goes to "L" level, the terminal CE connected thereto via the inverter 236 goes to "H" level, so that the down counter 235 The value "3" is subtracted in synchronization with the clock pulse CK2 [FIG. 2 (h)]. The countdown time of the down counter 235 is equivalent to three slots since the cycle of the clock pulse CK2 is equivalent to one slot. During this time, the frame counter 231 stops its operation because its terminal CE is at the “L” level.

When the time corresponding to three slots has elapsed, the count value of the down counter 235 becomes "0", and the output signal g returns to "H" level [FIG.
(E)]. As a result, the frame counter 231 resumes its operation from the state before the stop, so that the transmission timing signals e and f output from the decoder 232 are output in slots that are three slots behind the slots that should be output [FIG. (C), (d)], and in this case, the reception timing signals c and d are output in slots.
FIG. 2 (i) shows the use state of the time slot in the mobile station 2 during this time.

As described above, the frame counter 231 which receives the clock signal CK1 having a frequency of 384 KHz and generates an address synchronized with the frame timing, and decodes the address of the frame counter 231 to generate reception and transmission timing signals. A decoder 232;
A frequency dividing circuit 234 for generating a clock pulse CK2 for one time slot from the clock signal CK1 and a down counter 235 for counting down in synchronization with the clock pulse CK2 are provided, and the number of slots to be moved with respect to the down counter 235 is determined. The time slot is moved by setting and performing a countdown operation. As a result, the number of decoders conventionally provided for each time slot can be greatly reduced, and the multiplexer connected thereto can be reduced in size. Electricity can be realized.

[0034]

As described above, according to the present invention,
When the time slot of the mobile station is changed, the mobile station is provided with first and second counters, a decoder and a clock generation circuit, and the second counter always allows the first counter to generate a frame address. When a decoder connected to the first counter generates transmission and reception timing signals corresponding to each frame, and when a movement value based on a time slot movement request is set from the base station, 1 from the clock generation circuit is output. The movement value is counted in synchronization with the second clock of the time slot period, and the frame address generation operation is prohibited during this time. Therefore, when changing the time slot in the mobile station, a decoder having a large circuit scale is required. There is no need to provide each time slot, so the mobile station can be made smaller and the power consumption of the device reduced. Possible to become.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part of a mobile phone system according to the present invention.

FIG. 2 is a timing chart showing operation waveforms of each unit of the mobile phone system shown in FIG.

FIG. 3 is a block diagram of a mobile station included in the mobile phone system.

FIG. 4 is a diagram showing a format of data communicated by the mobile phone system.

FIG. 5 is a diagram showing a configuration of a mobile phone system.

FIG. 6 is a diagram illustrating transmission timing in a mobile phone system.

FIG. 7 is a block diagram of a circuit for generating various data transmission / reception timings in a conventional mobile station.

FIG. 8 is an output waveform diagram of the circuit shown in FIG. 7;

[Explanation of symbols]

 Reference Signs List 1 base station 21 to 24 mobile station 22 unique word detection unit 23 timing generation unit 24 reception CI inspection unit 27 reception data register 28 transmission data register 31, 32 speed conversion unit 33 audio processing unit 34 CPU 231 frame counter (first counter) ) 232 decoder 234 frequency divider (clock generation circuit) 235 down counter (second counter) 236 inverter TBS timing bus SBS system bus DB data bus a reception data b transmission data c, d reception timing signal e, f transmission timing signal g output signal h select signal CK1 clock signal (first clock) CK2 clock pulse (second clock)

Claims (1)

(57) [Claims] 1. A mobile telephone system comprising a base station and a plurality of mobile stations wirelessly connected to the base station, and performing data communication between the base station and the plurality of mobile stations in predetermined time slots. A first counter for inputting a first clock indicating a communication speed per bit of the data and generating a frame address for each of the time slots; A decoder for generating timing, a clock generation circuit for receiving the first clock and generating a second clock corresponding to one time slot, and always allowing a frame address generation operation of the first counter, A movement value based on a time slot movement request from the base station is set, and during the counting of the movement value based on the second clock, the first movement value is set. A second counter for prohibiting a frame address generation operation of the mobile station, wherein the mobile station changes a time slot of each mobile station based on a time slot movement request from the base station. Phone system.