JP3063563B2 - Scramble / descramble device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scramble / descramble process which performs scramble and descramble processes on burst signals transmitted through time slots each comprising a control physical slot and a communication physical slot. Related to the device.

[0002]

2. Description of the Related Art A telephone system to which this type of scramble / descramble device is applied employs a digital method for communication between a mobile station called PS and a base station called CS, and uses a digital system such as voice. Analog signal is AD converted and D
A conversion is performed and wireless communication is performed as a digital signal. FIG. 3 shows a configuration of such a 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.

Meanwhile, the radio frequency band is 1.9.
GHz band is used, and the carrier frequency interval is 3
00 kHz. 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 within 5 msec as shown in FIG. The first 4
The base station 1 transmits data to each mobile station in one of the four time slots, and receives data from each mobile station in the remaining four time slots. Such TDMA (time division)
Since the same frequency can be used by four mobile stations by multiple access processing, radio waves can be effectively utilized.

Here, as an example of a format of a burst signal communicated between a base station and each mobile station, the format is as shown in FIG. 5, and 240 bits are allocated to each time slot (1). Bit = 5 /
8 × 240 = 2.6 μsec), of which 224 data bits are provided. The burst signal communicated between the base station and each mobile station is generally scrambled and transmitted for the purpose of concealing data.

[0005]

In the case where such a scrambling process at the time of transmitting a burst signal and a descrambling process (descrambling process) at the time of receiving a burst signal are performed, the control physical shown in FIG. Since the scramble pattern applied to the burst signal is different from the standard in the slot and the communication physical slot shown in FIG.
It is necessary to select and switch each scrambling pattern before transmitting and receiving the burst signal, and the burst signal is transmitted at a high speed, so that there is a problem that the load on the CPU increases.

Accordingly, an object of the present invention is to reduce the load on the CPU when performing scramble processing and descrambling processing on a burst signal.

[0007]

SUMMARY OF THE INVENTION In order to solve such a problem, the present invention provides a first and a second method for scrambling a burst signal transmitted through a control physical slot and a communication physical slot. 2, a storage circuit for storing pattern data of No. 2; identification means for identifying whether or not the burst signal is a transmission burst signal via the control physical slot; and first and second memory circuits from among the storage circuits according to the identification output of the identification means. And selecting means for selecting one of the two pattern data. Also, a first and a second signal for descrambling a burst signal received via the control physical slot and the communication physical slot.
A first unique word having a first bit length included in a burst signal received through the control physical slot and a first unique word included in the burst signal received through the control physical slot, and received through the communication physical slot. A unique word detecting means for detecting any one of the second unique words having the second bit length included in the burst signal; and a first and a second memory from the storage circuit according to the detection output of the unique word detecting means. And selecting means for selecting one of the two pattern data. Also, the first pattern data for performing scrambling and descrambling processing on the burst signal transmitted through the control physical slot and the scrambling and descrambling on the burst signal transmitted through the communication physical time slot are performed. A storage circuit for storing second pattern data to be performed;
A first unique word having a first bit length included in a burst signal transmitted through the control physical slot and a second unique word included in a burst signal transmitted through the communication physical slot. Unique word detecting means for detecting one of the second unique words having a bit length, identifying means for identifying whether or not the burst signal is a transmission burst signal via a control physical slot, and identifying output of the identifying means And selecting means for selecting one of the first and second pattern data from the storage circuit in accordance with the detection output of the unique word detecting means.

[0008]

When the burst signal transmitted to the other station is identified as a transmission burst signal via the control physical slot, the first pattern data is selected from the storage circuit, while the transmission burst signal via the communication physical slot is selected. When identified, the second pattern data is selected, and a scramble process is performed on the transmission burst signal by each selected pattern data. As a result, for example, the CPUs provided in the base station and the mobile station do not need to switch the pattern data every time the burst signal is transmitted, and the load on the CPU is reduced. If the first unique word is detected from the received burst signal from the partner station and no synchronization burst is detected, the first pattern data is selected from the storage circuit while the first unique word is detected. A sync burst is detected or a second
Is detected, the second pattern data is selected, and the received burst signal is descrambled by each selected pattern data. As a result, it is not necessary for the CPUs disposed in the base station and the mobile station to switch the pattern data every time the burst signal is received, so that the load on the CPU is reduced. Also,
At the time of transmitting a burst signal, whether this burst is a burst via a control physical slot or a burst via a communication physical slot is identified, any pattern data is taken out from the storage circuit, and the transmission burst is scrambled. When the first unique word is detected from the received burst signal during reception,
When the first pattern data is selected from the storage circuit and the second unique word is detected, the second pattern data is selected, and the received burst signal is descrambled by each selected pattern data. As a result,
The CPUs provided in the base station and the mobile station do not need to switch the pattern data every time a burst signal is transmitted or received, so that the load on the CPU can be greatly reduced.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 2 is a block diagram showing one embodiment of the present invention.
1 shows an example of a mobile station 2 that performs wireless communication with a base station 1.
In the figure, a mobile station 2 includes an antenna AT and a high-frequency unit 2.
1, wirelessly connected to the base station 1 via a wireless unit including a modem unit 22, a wireless control unit 23, and a wireless interface unit 24. Here, a unique word detection unit 25 is connected to the wireless interface unit 24 via a timing bus TBS.
Timing generation unit 26, reception CI inspection unit 27, scramble unit 28, CRC processing unit 29, reception data register 3
0, transmission data register 31, transmission data coupling unit 32,
The simple secret unit 33, the speed conversion units 34 and 35, and the voice processing unit 36 are connected.

The system bus SBS includes the above-mentioned reception CI checking unit 27, transmission data connection unit 32, and speed conversion unit 3
Each part except for 4 and 35 is connected and the CPU 3
7. The operation unit 38 and the display unit 39 are connected. Further, a handset 40 and a ringer 41 necessary for a telephone call are connected to the voice processing unit 36, and the above-described units are connected to the power supply unit 4.
2 is operated by power supply. The unique word detection unit 25 and the timing generation unit 26 operate based on the 384 KHz clock signal CLK extracted by the wireless interface unit 24. Note that a and b respectively indicate received data and transmitted data when the mobile station 2 communicates with the base station 1.

The mobile station 2 configured as described above 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. 5 is a diagram showing a format of data transmitted / received to / from the base station 1 as described above. As data, 224 bits of information are transmitted / received per slot. Here, 16-bit data obtained by subtracting the above-mentioned 224-bit data from one-slot 240-bit data is used as a guard time for preventing data (transmission burst signal) from colliding between two adjacent slots. Used. By the way, the physical slot is roughly divided into a control physical slot and a communication physical slot, of which the control physical slot is used when transmitting and receiving control data, and the communication physical slot is used when transmitting and receiving voice data and the like. Can be

Here, the physical slot for uplink control from the mobile station to the base station has a 4-bit transient response ramp time R and a 2-bit start symbol S, as shown in FIG.
S, preamble PR of 62 bits, unique word UW of 32 bits, type signal CI of 4 bits, destination identification code of 42 bits, source identification code of 28 bits, control information I of 34 bits, and error detection of 16 bits CRC data (Cyclic Redundancy Check)
Are allocated. The downlink control physical slot is the same as the uplink control physical slot, except that a 42-bit calling identification code and a 28-bit destination identification code are allocated following the type signal CI.

As shown in FIG. 5B, the communication physical slot is assigned a ramp time R and a start symbol SS of 4 and 2 bits from the head, respectively, and then 6 bits, similarly to the control physical slot. Preamplifier 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 data CRC are allocated. In FIG. 5A and FIG. 5B, data from the head to the unique word UW indicates synchronous data.

Next, the operation of the mobile station 2 for transmitting data in the above-described format will be briefly described with reference to FIGS. When a wireless signal having a frequency of about 1.9 GHz is transmitted from the base station 1 to the mobile station 2, the wireless unit including the antenna AT, the high-frequency unit 21, the modem 22, the wireless control unit 23, and the wireless interface unit 24 High-frequency components are removed from the radio signal and demodulated to obtain a frequency of 38
Radio interface unit 2 as reception data a of 4 KHz
Output from 4.

The received data a is received by the unique word detecting section 25 and the received CI checking section 27. In each section, based on each reception timing output of the timing generating section 26, 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 26, and is used to generate timing required for subsequent data reception. Then, the generated timing signal is transmitted to the timing bus TB.
The signal is output to the transmission / reception processing units such as the scramble unit 28, the simple secret unit 33, and the voice processing unit 36 via S. in this case,
The scrambler 28 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 30.

In the CPU 37, 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 accumulated after the channel type CI stored in the reception data register 30 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 received data a, the unique word detecting unit 25 and the received CI checking unit 27 detect the unique word UW and the type signal CI indicating the type of the received data, and based on these detections, , And a scrambler 28, a CRC processor 29, and a speed converter 3
4 is configured to be able to operate without the intervention of the CPU 37.

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 33 and
The signal is expanded to a signal of 32 KHz by the speed converter 34, converted to an analog signal by the audio processor 36, and output from the handset 40.

Next, when the CPU 37 detects a transmission operation of the operation unit 38, the CPU 37 creates data based on the above-described format and outputs the data to the transmission data register 31. In the transmission data register 31, the timing generation unit 2
The transmission data is sent to the CRC processing unit 29 via the data linking unit 32 based on each transmission timing from No. 6. CR
The C processing unit 29 adds the error detection code CRC
Is transmitted to the scramble unit 28, and the scramble unit 28 applies DC balance to the transmission data and sends the transmission data to the radio unit such as the radio interface unit 24 as transmission data b. 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 with the base station 1 to call the partner terminal, and the call is started by the response of the partner. In this case, the audio signal from the handset 40 is converted into a digital signal with a frequency of 32 KHz by the audio processing unit 36, further compressed to a frequency of 384 KHz by the speed conversion unit 35, and sent to the simple privacy unit 33. The simple confidential section 33 performs confidential processing on the voice data and sends it to the transmission data linking section 32. Thereafter, the voice data is transmitted to the partner terminal via the base station 1 via the above-described route.

The scrambling and descrambling processing in the scrambler 28 is performed not only for the information I (that is, voice signal or data signal) and error detection data CRC of the communication physical slot shown in FIG. 5 in synchronization with the timing signal from the section 26.
This is also performed on the control data such as the destination identification code of the control physical slot shown in FIG.
The data patterns of scramble and descramble are different between the control physical slot and the communication physical slot. Accordingly, the CPU 37 causes the scramble unit 28 to select and set each pattern data and perform the scramble and descramble processing, but such processing increases the load on the CPU.

For this reason, in this embodiment, the load on the CPU 37 that causes the scrambler 28 to execute the scramble and descramble processing can be reduced. FIG.
FIG. 3 is a block diagram showing a main part of such a scramble unit 28, and is a block diagram of a scramble / descramble circuit 300. In the figure, the scramble / descramble circuit 300 is provided with a pattern initial value register 30.
1, the first selection circuit 302, PN
PN pattern generation circuit 303 for generating the pattern of (10, 3), second selection circuit 304, exclusive OR circuit 3
05, OR circuits 306 to 308, and AND circuit 30
9 to 312.

Next, the operation of the scramble / descramble circuit 300 will be described. First, the CPU 37 sets the pattern initial value register 30 during initial processing or the like.
The initial value of the scramble pattern is set to 1. Then, the pattern initial value is stored in the area A of the first selection circuit 302. This pattern is a scramble pattern of the communication physical slot, and is a pattern in which the first one bit (fixed to “1”) is added to the lower 9 bits of the calling identification code included in the downlink control physical slot information I. You. On the other hand, the area B of the first selection circuit 302 stores 10-bit data in which all bits are set to “1”. These 10-bit pattern data are repeatedly output during each of the scramble and descramble processes.

Here, when transmission burst data TDT to be transmitted to base station 1 is set in transmission data register 31 by CPU 37 as data of a control physical slot, and signal TCONH is set to "H" level, The “H” level signal is applied to the first selection circuit 302 via the OR circuit 308, and in this case, the pattern data stored in the area B of the first selection circuit 302 is sent to the PN pattern generation circuit 303. . That is, since the transmission burst data TDT is a transmission burst of the control physical slot, pattern data in which all the bits of the area B are “1” is sent to the PN pattern generation circuit 303.

In the PN pattern generation circuit 303, a clock signal CLK having a frequency of 384 KHz (not shown) and an "H" level scramble processing timing signal SCT from the timing generation section 26 via the OR circuit 306 are provided.
Generates a PN pattern in synchronization with the exclusive OR circuit 3
05 to one input terminal. Here, the transmission data T
DT is a transmission slot timing signal TSL for selecting a transmission slot of the mobile station from the timing generator 26.
The signal is output from the AND circuit 309 in accordance with the “H” level of T, and output to the other input terminal of the exclusive OR circuit 305 via the OR circuit 307.

As a result, in the exclusive OR circuit 305,
An exclusive OR of the generated PN pattern and the transmission data TDT is taken and output to the input terminal IN1 of the second selection circuit 304 as a scramble signal. And at this time,
Since the selection circuit 304 is selected by the scramble processing timing signal SCT at the “H” level and the AND circuit 311 is selected by the transmission slot timing signal TSLT, the selection circuit 304 is connected to the input terminal IN1 of the second selection circuit 304. The input scramble signal is output from its output terminal OUT to the base station 1 as a transmission data signal b shown in FIG.

The transmission burst data T to the base station 1
DT is set in the transmission data register 31 by the CPU 37 as synchronous burst data via the communication physical slot, and when the signal TCONH is set to the “L” level, this “L” level signal is transmitted through the OR circuit 308. Applied to the first selection circuit 302,
The pattern data stored in the area A of the selection circuit 302 is sent to the PN pattern generation circuit 303. That is, since the transmission burst data TDT is a transmission burst (synchronous burst) of the communication physical slot, the transmission data TDT is similarly scrambled by the pattern data of the area A and output from the AND circuit 311.

The transmission burst data T to the base station 1
DT is used as data via the physical communication slot by the CPU.
37, the transmission data register 31 is set.
When CONH is set to the “L” level, the logical sum circuit 3
The pattern data stored in the area A of the first selection circuit 302 is selected by the “L” level signal via 08. Then, the pattern data of this area A is sent to the PN pattern generation circuit 303 so that the transmission data TDT
Are scrambled and output from the AND circuit 311. When scrambling is not performed on a certain data area of the signal transmitted to the base station 1, the scramble processing timing signal SCT becomes “L” level. in this case,
Without passing through the exclusive OR circuit 305, the logical product circuit 30
9 and the second selection circuit 304 directly from the OR circuit 307.
The transmission data TDT itself input to the input terminal IN2 is output from the output terminal OUT via the AND circuit 311.

On the other hand, when the received data "a" shown in FIG. 2 from the base station 1 is detected as the received burst data RDT, the unique word UW in the received data is 32 bits, and the type signal CI is not a synchronous burst. Is detected and the signal UW32S becomes “H” level,
The output of the OR circuit 308 becomes "H" level. When the “H” level signal is applied to first selection circuit 302, the pattern data stored in area B of first selection circuit 302 is converted to PN pattern generation circuit 30.
Sent to 3. That is, since the received burst data RDT is a received burst of the control physical slot, the pattern data of the area B in which all bits are “1” is sent to the PN pattern detection circuit 303. Here, the PN pattern generation circuit 303 generates a PN pattern in synchronization with the “H” level descrambling processing timing signal DSCT from the timing generation unit 26 via the OR circuit 306, and Output to one input terminal.

The reception data RDT is transmitted to the timing generator 2
6 is output from the AND circuit 310 in accordance with the “H” level of the reception slot timing signal RSLT for selecting the reception slot of the mobile station from the input terminal 6 and the other input terminal of the exclusive OR circuit 305 via the OR circuit 307 Output to As a result, the exclusive OR circuit 305 takes an exclusive OR of the generated PN pattern and the received data RDT, and generates a descrambling signal as the second selection circuit 30.
4 to the input terminal IN1. At this time, the selection circuit 304 has been selected by the descrambling processing timing signal DSCT of “H” level, and the AND circuit 312 has been selected by the reception slot timing signal RSLT. The descrambling signal input to the input terminal IN1 is output from the output terminal OUT to the reception data register 30 shown in FIG.

In the burst data RDT received from the base station 1, the unique word UW is 32 bits,
When it is detected that the type signal CI is a synchronous burst, the pattern data stored in the area A of the first selection circuit 302 is sent to the PN pattern generation circuit 303. Similarly, the received data RDT is scrambled by the PN pattern output from the PN pattern generation circuit 303 by the pattern data, and the logical product circuit 3
12 is output.

If it is detected in the received burst data RDT from the base station 1 that the unique word UW is 16 bits, this is a received burst of a communication physical slot, and therefore, the signal UW32S becomes "L". Level, the pattern data stored in the area A of the first selection circuit 302 is sent to the PN pattern generation circuit 303. And similarly, P
Received data RDT is scrambled by the PN pattern output from N pattern generation circuit 303 and output via AND circuit 312. When descrambling is not performed on a certain data area of the received data signal a from the base station 1, the descrambling processing timing signal D
SCT becomes “L” level. In this case, the received data does not pass through the exclusive OR circuit 305 and the logical product circuit 31
0 and the second selection circuit 304 directly from the OR circuit 307
The received data RDT itself input to the input terminal IN2 is output from the output terminal OUT via the AND circuit 312.

As described above, in this embodiment, the first pattern data for scrambling and descrambling the transmission / reception burst signal of the control physical slot is stored in the area B of the first selection circuit 302, and the communication physical The second pattern data for scrambling and descrambling the transmission / reception burst signal of the slot is provided to the first selection circuit 30.
When transmitting a burst signal, it is determined whether the burst is a burst via a control physical slot or a burst via a communication physical slot, and any pattern data is extracted to perform a scrambling process on the transmission burst. In addition, at the time of burst reception, one of the first and second pattern data is taken out according to the number of bits of the unique word UW included in the burst signal and the type signal CI, and the descrambling process is performed on the received burst signal. is there. As a result, CP
Since U37 does not need to select and set pattern data every time a burst signal is transmitted and received, and only needs to be set during initial processing, the load on the CPU 37 during scramble and descramble processing can be greatly reduced.

In this embodiment, an example in which the scramble / descramble circuit 300 is applied to the mobile station 2 has been described. However, the base station 1 is also configured by the same hardware as the mobile station 2 and transmits and receives data. Since the data format is the same, it is clear that the scramble / descramble circuit 300 can be applied to the base station 1.

[0035]

As described above, according to the present invention, when a burst signal transmitted to a partner station is identified as a transmission burst signal via a control physical slot, the first pattern data is selected from the storage circuit. In addition, when the second pattern data is identified as a transmission burst signal via the communication physical slot, the second pattern data is selected, and the scramble process is performed on the transmission burst signal by each selected pattern data. The CPU provided in the mobile station or the like does not need to switch the pattern data every time the burst signal is transmitted, and thus the
The load on U can be reduced. When the first unique word is detected from the burst signal received from the partner station, the first pattern data is selected from the storage circuit while the second pattern is selected.
When the unique word is detected, the second pattern data is selected, and the scramble of the received burst signal is descrambled by each selected pattern data. There is no need to switch pattern data every time a signal is received, so that the load on the CPU can be reduced. Also, at the time of transmitting a burst signal, while discriminating whether this burst is a burst via a control physical slot or a burst via a communication physical slot, one of pattern data is selected from a storage circuit, and a scrambling process for a transmission burst is performed. At the time of burst reception, pattern data corresponding to one of the first and second unique words detected from the received burst signal is selected from the storage circuit to descramble the received burst signal. It is not necessary for the CPUs disposed in the station and the mobile station to switch the pattern data every time a burst signal is transmitted / received, so that the load on the CPU can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a block diagram of a mobile station to which the circuit of the embodiment is applied.

FIG. 3 is a block diagram of a digital cordless telephone system including the mobile station.

FIG. 4 is a timing chart showing data communication timing in the system.

FIG. 5 is a diagram showing a format of a burst signal communicated in the system.

[Explanation of symbols]

1 ... base station, ₂₁ to ₂₄ ... mobile station 25 ... unique word detector, 26 ... timing generator, 27 ... receiving CI inspection unit, 33 ... simple privacy unit, 37 ... CPU, 36 ... audio processing unit, 300: Scramble / descramble circuit, 3
01: pattern initial value register, 302: first selection circuit, 303: PN pattern generation circuit, 304: second selection circuit, 305: exclusive OR circuit, 306 to 308 ...
OR circuit, 309 to 312... AND circuit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04B 7/26 H04J 3/00 H04K 1/00 H04L 9/00 H04Q 7/00-7/38

Claims (3)

(57) [Claims] 1. A scrambling device for scrambling a burst signal transmitted via a time slot having each of a control physical slot and a communication physical slot, wherein the control physical slot and the communication physical slot are A storage circuit for storing first and second pattern data for scrambling a burst signal transmitted through the control unit, and identifying whether or not the burst signal is a transmission burst signal via the control physical slot Identification means; and selection means for selecting one of the first and second pattern data from the storage circuit in accordance with the identification output of the identification means, and a scrambling process for a transmission burst signal is performed by the selected pattern data. And a scrambler device. 2. A descrambling device for performing a descrambling process for descrambling a burst signal received via a time slot having each of a control physical slot and a communication physical slot. A storage circuit for storing first and second pattern data for descrambling a burst signal received through a slot and a communication physical slot, and a burst signal received through the control physical slot And a second unique word having a second bit length included in a burst signal received through the communication physical slot and having a first bit length. A unique word detecting means for detecting one of them, and And selecting means for selecting either one of the first and second pattern data from the memory circuit, the descrambling apparatus characterized by descrambling the received burst signal by the selected pattern data. 3. A scrambling / descrambling device for performing each processing of scrambling and descrambling on a burst signal transmitted through a time slot including each of a physical slot for control and a physical slot for communication. A first pattern data for performing scrambling and descrambling processing on a burst signal transmitted through a physical slot and a scramble and descrambling for a burst signal transmitted through the communication physical time slot; A storage circuit for storing second pattern data, a first unique word having a first bit length included in a burst signal transmitted through the control physical slot, and the communication physical slot. The second bit included in the burst signal transmitted by Unique word detecting means for detecting any one of the second unique words having the same length, identifying means for identifying whether the burst signal is a transmission burst signal via the control physical slot, and identifying means for the identifying means. Selecting means for selecting one of the first and second pattern data from the storage circuit in accordance with the identification output and the detection output of the unique word detecting means; A scramble / descramble device, which performs scramble processing.