JPH06101719B2 - Control information transmission method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to time division multiple access communication or random access packet satellite communication, and more particularly to a control information transmission method for a system using a synchronous code in burst data.

[Conventional technology]

For time division multiple access satellite communication and random access packet satellite communication using the conventional multi-phase PSK modulation method, Radio Research Institute Quarterly Report Vol.28, NO.145, pages 31 to 38 (March 1982)
"CS-based computer network experiment system" and R & D report of Nippon Telegraph and Telephone Public Corporation Vol. 32, No. 4, No. 86
Synchronize system control information such as station identification information (station address) and burst type identification information as described in "Design of earth station equipment for SS-TDMA system" from page 1 to page 873 (1983). Transmission using a dedicated code other than the code, or inversion of the synchronization code (inversion of code element "1", "0")
I'm using it to communicate. That is, both require multiple code slots and multiple code detections.

[Problems to be solved by the invention]

In the system using the code for control information in addition to the synchronous code as in the above-mentioned conventional technique, two code detectors are required. Further, in the method using the inversion of the synchronization code, the number of information patterns is small and the amount of information that can be transmitted is small. Further, both of them have various problems that the frame efficiency is lowered by increasing the code slots.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a control information transmission method capable of transmitting various control information by using a synchronization code slot capable of accommodating only one synchronization code. .

[Means for solving problems]

When transmitting control information such as station identification information and burst type identification information, the purpose is to set the start point of the burst synchronization code in a plurality of parallel code strings corresponding to the number of modulation phases in correspondence with various control information. It shifts for each code string, and transmits this shift amount as control information.
This is achieved by detecting the synchronous code from the demodulated signal by the synchronous code detector for each parallel code string, detecting the shift amount of the synchronous code start point from the time difference between the respective detection signals, and acquiring the control information.

[Action]

Since the starting point shift amount of the synchronization code in a plurality of parallel code sequences is changed according to the type of control information, it is not necessary to increase the number of code slots according to the number of types of control information, and the synchronization code is set to control information. Since it is used as a code for use, it is not necessary to use many code detectors, and more information patterns can be acquired.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

The TDMA satellite communication system using the 4-phase PSK modulation system will be described as an example. In four-phase PSK modulation, modulation is performed with two parallel code strings of P channel and Q channel, and the modulation phase state is
It is determined by the four code patterns of (P, Q) (, Q) (,) (P,). At the beginning of the burst data used for transmission, there is a burst synchronization code (hereinafter abbreviated as UW), which is used for phase uncertain removal during demodulation and frame synchronization by making it correspond to the four code patterns. The present invention pays attention to the start point of each code, not to the P and Q code patterns, and transmits various information by shifting the UW code start point in accordance with the station identification information or burst type identification information to be transmitted. To do.
For example:

The UW used is UP = (a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ ) UQ = (b ₀ , b ₁ , b ₂ , if the P channel is UP and the Q channel is UQ. _{b 3, b 4, b 5} ) the normal synchronization code. If the control information is not included, the UW components are a ₀ and b ₀ , a ₁ and b ₁ , a ₂ and b ₂ , and P,
Q Make sure that the two channels have the same time, that is, the code start points are the same. Next, when sending the identification information of NO.1, UP = (a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , *) UQ = (*, b ₀ , b ₁ , b ₂ , b ₃ , b ₄ , b ₅ ). Note that * is an invalid bit. In this case, the UQ code start point is shifted by 1 bit with respect to UP. Next, when sending the identification information of the station NO.2, UP = (a ₀ , a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , *, *) UQ = (*, *, b ₀ , b ₁ , b ₂ , b ₃ , b ₄ , b ₅ ). In this case, the code start point of UQ is shifted by 2 bits with respect to UP. As described above, the shift amounts of the UP and UQ code start points are used as station identification information. In the burst receiving station, UW detection is performed for each P and Q channel from the demodulated signal, and UP,
By measuring the time difference between the UQ detection signals in bit units, it is possible to detect the code start point shift amount of UP and UQ and obtain the station identification information. Note that UW of UP and UQ can be burst-synchronized (in the sense of identifying the beginning of data) by determining the maximum shift amount in advance, and can also be used to eliminate phase uncertainty during demodulation. Can be used as usual.

Next, the above embodiment will be described more specifically. Burst signals used for TDMA satellite communication and packet satellite communication are
Generally, a burst basic structure 5 as shown in FIG. 2 is used, CR is used as a carrier recovery symbol, BTR is used as a clock recovery symbol, UW is used as a synchronization code, and DATA is used as traffic data and control data. In particular, 4-phase PSK modulation (2
When phase PSK modulation is excluded), the modulation is performed by the code strings of P and Q2 channels, so UW is as shown in FIG.
It constituted by _{(a 0 a 1 ...... a 7} ) and _{(b 0 b 1 ...... b 7} ) the synchronization code bit 6 concurrent in. In general, (a ₀ ......
a ₇₎ and (b ₀ ...... b ₇₎ to using the same reference numerals are simplified configuration of a UW detector. FIG. 1 shows an example in which burst type identification information can be transmitted according to this embodiment. FIG. 3A shows a data burst for transmitting traffic data, which is regarded as a normal burst and is a UW in the sync code slot.
Match the sign start points of. Note that the maximum amount of the shift width in other bursts is fixed, and invalid bits (indicated by *) for the shift width are inserted. The same figure (b) shows the reserved burst that can identify the station No. 1. The UW code start point is shifted by 1 bit between the P and Q channels, and the sync code shift width is set to t _1. It is used as NO.1 identification information. FIG. 7C is a reserved burst capable of identifying the station No. _2, and the station No. 2 identification information is obtained by shifting the code start point of the UW by 2 bits and setting the sync code shift width to t ₂ . As described above, the burst type identification information can be transmitted by changing the shift width t of the parallel code.

At the burst receiving station, the code shift width is detected by the circuit shown in FIG. Received data demodulated by the Q-PSK demodulator 7 is converted into UW and
UW of FIG. 1 by the synchronous code detector 8 capable of detecting ▼
Detects (a ₀ …… a ₇ ) and (b ₀ …… b ₇ ) and detects pulse U
Get P, ▲ ▼, UQ, ▲ ▼. In consideration of the phase uncertainty at the time of demodulation, a synchronous code or a synchronous code detector is selected so that UW detection can be performed even when the P and Q channels in FIG. 1 are exchanged. UP detection pulse and ▲ ▼, UQ
And ▲ ▼ are summed by the OR gate 9 so that the detection pulse is output when either positive or negative pattern can be detected. As a result, the sync code shift width detector 10
The amount of UW shift between P and Q channels is detected, and Fig. 1 (a)
Identify any of the patterns from (c) to (c). In this way, transmission of system control information such as burst type identification information and station identification information is distinguished by the UW shift amount.

FIG. 4 shows the state where the pattern of FIG. 1 (c) is received, and the synchronous code detection pulse UP (▲ ▼) of UW (a ₀ ...... a ₇ ) and UW (b ₀ ...... b ₇ ). And UQ (▲ ▼) time difference t '
Is 2 bits, which makes it possible to identify that it is a reserved burst for station No.2. Note that FIG. 5 similarly shows reserved burst detection of the station No. 2, but in this case, the P and Q channels have a code pattern (, P) that is switched due to phase uncertainty during demodulation. . At this time, as in FIG. 4, the code start point shift amount t'between both P and Q channels can be detected.

〔The invention's effect〕

According to the present invention, by using one burst synchronization slot in a burst and a synchronization code detector for each parallel code sequence, burst synchronization, frame synchronization and phase uncertainty removal which are basic functions of the synchronization code are performed. It is possible to transmit control information such as station identification and burst type identification without losing each of the above functions, and there is an effect that the frame utilization efficiency is higher than other methods using complex synchronization codes and the like.

[Brief description of drawings]

1 (a), (b), and (c) are transmission identification diagrams of burst identification information according to an embodiment of the present invention, FIG. 2 is a basic configuration diagram of burst, and FIG. 3 is a burst identification information detection circuit. FIG. 4 is a block configuration diagram of FIG. 4, FIG. 4 is a burst identification information detection system diagram, and FIG. 5 is a burst identification information detection system diagram when the code pattern is inverted due to phase uncertainty during demodulation. 1 ... Slot for accommodating synchronization code 2 ... Slot of information data 5 ... General burst basic configuration 6 ... Synchronization code element 7 ... Q-PSK demodulator (4-phase PSK demodulator) 8 ... Synchronization Code detector, 9 ... OR gate 10 ... Synchronous code shift width detector

Claims (1)

[Claims] 1. A control information transmitting method for transmitting and receiving arbitrary information between a transmitting station and a receiving station, which is time division multiple access communication or random access packet communication by a multi-phase PSK modulation method, wherein the transmitting station The start point of the synchronization code located at the beginning of the parallel code sequence forming the burst data to be transmitted is shifted bit by bit for each parallel code sequence, and the shift amount is changed according to various system control information before transmission. In the receiving station that receives the burst data and the synchronization code located at the head of the burst data, the system control information is detected by detecting the shift amount of the synchronization code for each code sequence from the demodulated parallel code sequence. The method for transmitting control information is characterized in that