JPS60250735A - Scanning beam tdma radio communication system - Google Patents

Abstract

PURPOSE:To transmit a synchronizing signal in a prescribed format and to improve the communication efficiency of TDMA communication by using a non- directional or form block antenna for a descending circuit from one station to plural stations and a scanning beam antenna for an ascending circuit from plural stations to one station. CONSTITUTION:A 90 deg. fan beam pattern 10 for a descending line is used for the descending circuit of one station, a scanning beam pattern 11 for an ascending circuit is used for the ascending circuit and the 90 deg. range is covered with n beams and scanned at a high speed to execute TDMA communication. A synchronizing signals 8 is arrayed on the head of a frame format to be used for the communication, plural bursts are arranged after the signal 8 and control bursts 9 and a pre-amble 7 are formed in the bursts 5. Thus, signals outputted from plural stations in the descending circuit within the 90 deg. range can be always received by one station, which extracts respective synchronizing signals 8, detects the position of the control burst 9 of the station itself and sends an originating signal or the like by the burst 9.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a TDMA wireless communication system that covers a wide area by combining a scanning beam antenna and an omnidirectional antenna or a shaped beam antenna.

(Background Art) Conventionally, so-called point-to-multipoint T between one station 1 and multiple stations 2 as shown in FIG.
In the DMA wireless communication system, the antenna for one station 1 is an omnidirectional antenna, a shaped beam antenna,
Scanning beam antennas, etc. were not used. However, omnidirectional antennas and shaped beam antennas, such as the 90° fan-shaped beam 3 in Figure 1, emit radio waves over a wide range, so they cannot be used with sharp beam antennas used for point-to-point communications. Since the antenna gain is small compared to the above, in order to obtain the required communication quality, the antennas of multiple stations 2 must have large diameters and high-performance transceivers are required, making it an economical and easy-to-install system. The disadvantage was that it could not be configured. On the other hand, Fig. 2 (α)
When a scanning beam antenna is used to irradiate a 90° range with n beams 4 as shown in Figure 2(b), and when performing TDMA communication by scanning at high speed as shown in Figure 2(b), Since there are multiple stations 2, 2' or 2", 2', the TDMA frame format needs to be configured as shown in Figure 3. Here, P is the preamble, D is the data burst, and F is the frame format shown in Figure 3. indicates a frame burst, and C indicates a control burst.In other words, since it is divided into m basic bursts 5 and the scanning beam is switched for each basic burst, it is necessary to provide a preamble 7 in addition to the data burst 6 for each basic burst. The preamble consists of a synchronization signal 8 for TDMA synchronization and a control signal 9 for TDMA line control, which reduce the original communication capacity.
This has the disadvantage of reducing transmission efficiency (frequency usage efficiency).

Furthermore, DA performs TDMA line control each time a call occurs.
(Variable Allocation) - The TDMA system has the drawbacks that its control is extremely complicated and the amount of hardware for the device is also large. In order to solve these problems, it is possible to set up separate wireless channels for synchronization signals, control signals, etc. and transmit them using omnidirectional antennas, but this would require two transmitters and receivers, and it would be difficult to synchronize. There are drawbacks such as decreased accuracy.

(Problems to be solved by the invention) In order to solve these drawbacks, the present invention performs TDM communication using an omnidirectional antenna or a shaped beam antenna for lower multi-line communication from one station to multiple stations. It is characterized by the use of scanning beam antennas for multiple lines from one station to another to perform TDMA communication, and its purpose is to realize an economical and highly efficient transmission multipoint wireless communication system. It is in.

(Structure and operation of the invention) FIG. 4 shows an embodiment of the present invention, and FIG. This embodiment shows a case where TDK communication is performed using a 90° fan beam antenna. Fourth
Figure (b) shows the pattern of a scanning beam antenna for one station used in a multi-channel system.
Performs MA communication.

That is, with the frame configuration as shown in FIG. 5, multiple stations 2 within 90 degrees can always receive the signals of the lower multiple lines.
Then, the TDMA synchronization signal is extracted, the position of the control burst 9 used by the own station can be known, and the control burst can be used to transmit a calling signal or the like and start communication. In FIG. 5, F is a frame burst, C is a control burst, and D is a data burst. At this time, it is necessary that the scanning beam antenna for the upper line directs its beam toward the station, and the scanning beam scans at high speed in synchronization with the TDMA frame. In the case of the PA (fixed allocation)-TDMA system, this scanning may be performed in a predetermined order, but in the DA (variable allocation)-TDMA system, the siburst allocation is variable depending on the occurrence of a call, so the scanning order is will also be scanned according to the assignment. That is, the scanning order is determined by TDMA burst allocation under the control of one station.

Since the signals for this purpose are always transmitted to a plurality of stations through multiple lines, it is possible to easily follow not only one station but also a plurality of stations, and control can be performed easily.

Although the explanation here has been limited to a range of 90 degrees, the same applies to the case of a full circumference of 360 degrees. Furthermore, it is also possible to emit a scanning beam in each 90° range, emit four scanning beams simultaneously on the entire circumference, and perform TDMA communication independently every 90°.

(Effects of the Invention) As explained above, in the frame format of the present invention, the synchronization signal 8 only needs to be provided at the beginning of the frame as shown in FIG. Since the number can be reduced, good transmission efficiency can be achieved. Well, the downlink is always formed, so line control commands can be easily transmitted, and TD
MA line control becomes simple and the amount of hardware can be reduced. In addition, omnidirectional antennas for upstream and downstream lines,
Alternatively, compared to the case where a shaped beam antenna is used, the transmission power of the uplink, that is, the transmission power of the plurality of stations 2 can be smaller than that of one station, and the device configuration can be simplified. The cost for one line in this type of system is as follows: Since the equipment of one station is shared by multiple stations,
The equipment cost of multiple stations has a large influence, as is the sum of the equipment cost of one station divided by multiple cycles and the equipment cost of multiple stations. The present invention has the advantage that the cost of equipment for a plurality of stations is significantly lower than that of the conventional system as described above, and that a point-to-multipoint wireless communication system can be realized with low cost per line.

[Brief explanation of the drawing]

No.! 22, is a diagram showing the configuration of a general point-to-multipoint wireless communication system, and Figures 2 and 3 are an example of the configuration of a TDMA wireless communication system using a conventional scanning beam antenna and an example of its frame format. FIGS. 4 and 5 are diagrams showing a configuration example and a frame format example in an embodiment of the present invention. ■...One station, 2...Multiple stations, 3...90
゛' Fan beam pattern, 4... No turn of scanning beam, 5... Basic burst, 6... Data burst, 7... Preamble, 8... Frame burst, 9... Control - Strike, 10...90 for downlink
0 No turn of fan-shaped beam, 11 ...No (turn of scanning beam for upper 9 lines. Patent applicant Nippon Telegraph and Telephone Public Corporation Patent application representative Patent attorney Megumi Yamamoto - Curtain f illustration, Figure 2 ((1) ( b) Qin 3 figure 5 Xiang 4 figure raノ (b)

Claims (4)

[Claims] (1) In a wireless communication system between one station and multiple stations, communication from the multiple stations to one station uses an antenna beam with a beam width sufficiently narrow across the communication target area. TDMA communication is performed by scanning the beam at high speed for multiple communication targets within the target area, and communication from one station to multiple stations is performed by covering the antenna beam with a smaller number of beams than the number of communication target stations. Fixed, T
Scanning beam TDMA characterized by performing DA4 communication
Wireless communication method. (2) Communication from multiple stations to one station is performed using TDM by scanning at high speed so that multiple antenna beams with beam widths narrower than the communication target area exist simultaneously.
The scanning beam TDMA wireless communication system according to claim 1, characterized in that A communication is performed. (3) Beam scanning order and number of scans are predetermined T
3. The scanning beam TDMA wireless communication system according to claim 1, wherein the scanning beam TDMA wireless communication system is synchronized with the DMA time slot allocation order and the allocated number. (4) The scanning beam TDMA radio according to claim 1 or 2, characterized in that the beam scanning order and the number of scans are synchronized with the TDMA time slot allocation order and the allocated number according to the occurrence of a call. Communication method.