JPH04207421A - Diversity system - Google Patents

Abstract

PURPOSE:To eliminate the need for a special control circuit for antenna changeover by providing a means to discriminate whether or not an identification signal is returned to a transmitter and selecting other antenna so as to implement data transmission when no identification signal is detected. CONSTITUTION:A transmitter is provided with a transmission section 405 and a receiver is provided with a reception section 406 respectively, the transmitter has at least plural transmission reception antennas 401, 402, and a means 407 discriminating whether or not an identification signal is returned from the receiver is provided to the transmitter when a data is sent from one antenna 401 of the transmitter and other antenna 402 is selected by a changeover switch 404 when no identification signal is detected. Thus, when a data signal sent from the one antenna 401 of the transmitter is correctly received by the receiver, the receiver sends an identification signal to the transmitter, and when the transmitter cannot receive the identification signal, the other antenna 402 is selected and a data is sent. Thus, a special control circuit for antenna changeover is not required.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a diversity system suitable for wireless protocol communication.

[Summary of the Invention] Data transmission is performed when an ACK (identification signal indicating correct reception) cannot be received correctly from the data receiving side in a diversity system using antenna switching in wireless packet communication for the data sending side. The side antenna can be switched.

[Prior Art] Fig. 0 and Fig. 11 illustrate the conventional tie diversity system. In FIG. 10, +01 is a transmitter, 102 is a transmitting antenna, 103 and 104 are receiving antennas, and 10
5 and 106 are high frequency circuit sections, 107 is a receiving state comparison circuit, +08 is a changeover switch, and +09 is a demodulation circuit.

Further, in FIG. 11, 201 and 202 are receiving antennas, 203 is a high frequency circuit section, 205 is a reception judgment comparison circuit,
204 is a changeover switch, and 206 is a demodulation circuit.

On the receiving side in Fig. 10, two antennas 103° and 104
The receiving state comparison circuit 107 determines from which antenna the received signal is better, and the better one is selected by the selector switch 108. In FIG. , 106 becomes large in scale, they may be configured as shown in FIG. 11. In FIG. 11, the antenna 201 initially receives the signal, and when the reception condition becomes poor, the reception condition comparison circuit 205 makes a determination and switches to the antenna 202.

[Problems to be Solved by the Invention] Regardless of which method is used, a control circuit such as circuit 107 or 205 for switching the changeover switch is required, and even when control is performed by a microcomputer, , it is necessary to prevent proper sensor circuitry. Furthermore, the performance also largely depends on the control circuit or sensor, which has the disadvantage of being difficult to design.

[Object of the Invention] An object of the present invention is to provide a diversity method for use in wireless packet communications that does not require a special control circuit for antenna switching.

[Means for Solving the Problems] In order to achieve the above object, the diversity system of the present invention includes a data transmitter and a data receiver each having a transmitter and a receiver, and at least the data transmitter has a plurality of The data transmitter has a transmitting/receiving antenna, and when data is transmitted from one of the antennas of the data transmitter, the data transmitter has means for determining whether an identification signal is returned from the data receiver, When no signal is detected.

5 [Operation] When the data signal transmitted from one antenna of the data transmitter is correctly received by the data receiver, the data transmission is performed by switching the data transmission to the other antenna. An identification signal (ACK) is sent to the data transmitter.

If the data transmitter cannot receive the above identification signal, it will switch to another antenna and transmit data. First, let's briefly explain packet communication.2 Figure 2 shows the simplest protocol for packet communication between station A and station B.Packet communication means dividing the data to be transmitted into small pieces, and transmitting the data to each small piece. It adds a ladder including source, destination, data number, etc., and sends it like a packet (parcel).

In Figure 2, the packet (data) of the station A's construction number day is
In response to the transmission of , station B correctly receives this and returns an ACK from station B, and the ACK is correctly received by station A. Station A starts a timer from data transmission and sends an ACK
The time T until the packet can be received is monitored, and when T reaches a predetermined time Tw, it is determined that there is a failure in the propagation path and the same packet (data) is retransmitted. In FIG. 2, T was shorter than Tw, so no retransmission occurs for the first packet (data).

Next, assume that when the second packet (data) is transmitted from station A, it cannot be received at station B due to a failure in the propagation path. In this case, no ACK is received and T2
Since the second packet (data) has been reached, station A retransmits the second packet (data). FIG. 2 shows that ACK has been correctly received for retransmission.

Figure 2 shows a case where a propagation path failure occurs in transmission from station A to station B, but when ACK is received from station B,
Even if a failure occurs when transmitting to station A, station A will still be unable to receive the ACK, so it will be retransmitted. In this case, station B will receive the same packet (data) twice, but this itself is not a problem.

Although the protocols of packet communications actually performed are more complex, the basic idea of using ACK and retransmission is common to all T packet communications.

The diversity system of the present invention is suitable for wireless packet communication using such a protocol, and a transmitter of one embodiment thereof is shown in FIG. In the same figure, 4Ol and 402 are antennas, 403 is an antenna changeover switch, 404 is a transmission/reception changeover switch, 405 is a transmitter, 406 is a receiver, and 40
7 is a microcomputer 5 The microcomputer 407 performs protocol control other than diversity, such as packetization of transmission data and depacketization of reception data, and diversity control.

The specific target of diversity control is the antenna changeover switch 4038. Furthermore, the transmission and reception changeover switch 404 is also
Although it is controlled by the microcomputer 407, it is only controlled by the transmitting side T at the time of transmission and by the receiving side R at the time of reception, and is not a component of the present invention, so a description thereof will be omitted.

FIG. 3 illustrates the operation of the above embodiment in the manner shown in FIG. As shown in FIG. 3, when an ACK corresponding to data transmission cannot be received, the connection of the antenna changeover switch 403 to the previous antenna is switched to the other antenna and retransmission is performed. In Figure 3, the ACK for the second bucket (data) could not be received, so when the antenna was switched, the propagation path was better, so the data could be transmitted correctly with one retransmission. It indicates that it has been completed. FIG. 4 is a flowchart showing the operation of FIG. 3 as a general operation of the microcoscipiputer 407. In step 601 of FIG. 4, the microcomputer 407 sets the initial state in which the antenna changeover switch 405 is connected to one antenna (thereby determining whether it is data transmission or reception in step 602), whether it is data transmission or not. Step 612), YE
If S, ACK transmission and data processing (step 613
).

When it is determined in step 602 that data is to be transmitted, the data processing is performed in step 603, and then a timer is started (steps 604, 605) and a timer to transmit packets with K=1 to 1 (step 606).

This allows the reception of ACK to be determined (step 607),
If YES, the transmission ends (step 610) and the process returns to step 602, or the process returns to step 605 by setting = to +1 in step 611.

If the determination in step 607 is NO, it is determined whether or not the timer time has reached Tw (step 608);
If YES, the process returns to step 607; however, if YES, the antenna changeover switch 403 is switched to the other antenna (step 609), and the process returns to step 605.

The above operation is when the antenna is switched only on the data transmitting side, and as shown in Figure 5, the data flow is from station A to station B only (or mostly from station A to station B). If there is no need to perform diversity at station B, or if diversity is not possible at station B for some reason (such as not being able to use two antennas), station A
This is suitable for switching between route 1 and route 2 and selecting a better propagation path. Also, as shown in Figure 6, station A,
Even if station B both has diversity functions,
Since only the side sending the data has control, (6th
The figure shows the case where station A also sends data)
It is possible for station A to switch between route 1 and route 2, or between route 1 and route 2''. However, even if both station A and station B have diversity functions, For example, as shown in FIG. 7, four propagation paths, route 1 to route 4, can be selected, which is more effective in that more propagation paths can be selected.

To perform the operation shown in FIG. 7, the microcomputer may be operated on the side sending the ACK, such as switching the antenna.

A flowchart of the operation of the embodiment in such a case is shown in FIG. In the same figure, steps 601, 602, 612
, 613 are similar to those in FIG. 4, and further step +00
1,1002.1003 actions have been added.

That is, when data is received, it is determined whether or not K is the same (step 1001). If NQ, the process goes to step 613, but if YES, if the number of retransmissions is M or more, the process goes to step 613. 1002), antenna selector switch 4
03 to the other antenna (step 1.003
).

In addition, in Fig. 7, ni is the number of the transmitted data, and
This corresponds to K in step 605 in the figure, and is included in the header and transmitted. It is also assumed that the number of retransmissions at station A is also included in the header and transmitted together with the data. N1 of step +002 may be appropriately determined to be 2 or more. If the ACK is impaired and the ACK is not received by station A in FIG.
Four route selections as shown in FIG. 7 are possible.

FIG. 9 is an example of the operation of the expanded diversity method according to the flowchart of FIG. In Fig. 9, [α, β] of station A, α is the number of retransmissions, and β is the number of retransmissions of station A.
The antenna (A-1 or A-2) used in station B
The antenna used for station B (B-1 or B
-2), DK represents the second data, and X represents the failure. In FIG. 9, when the propagation path by the combination of antennas A-2 and B-2 is optimal, the operation is shown to reach the optimal propagation path.3 Note that in FIG.

The case where N1 in step 1002 in FIG. 8 is 2 is shown.

In the present invention, as the tie diversity for switching between seven antennas, known techniques such as space tie diversity, polarization diversity, and directional tie diversity can be used. In addition, in the explanation, there are two antennas, but even if there are three or more antennas, step 609 in FIG. 4 and step l003 in FIG. The larger the number, the more effective it is in that more propagation paths can be selected.

Furthermore, although a microcomputer is used in the above embodiment, it is natural to use a microcomputer for protocol control in packet communication, and from a hardware point of view, a switching control circuit is not required as in the conventional case. It is possible to realize a low-cost, high-performance diversity system by using only a plurality of antennas and an antenna switching circuit. A diversity method suitable for wireless packet communication can be provided.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is an explanatory diagram of packet communication, Fig. 3 is an explanatory diagram of the operation of the above embodiment, and Fig. 4 is an illustration of the operation of the microcomputer in the above embodiment. Flowcharts shown in FIGS. 5, 6 and 7
8 is a flowchart showing the operation of another embodiment of the present invention, FIG. 9 is an explanatory diagram of the operation of the other embodiment, and FIGS. 1st
FIG. 1 is a block diagram showing each conventional diversity method. 401.402...Antenna, 403...
...Antenna selector switch, 404...Transmit/receive selector switch, 405...Transmitter section, 4
06...Receiving section, 407...Microcomputer. Fig. 1 401 , 402 Anti 1 403 Anti-grip learning 404, friend tσV switch 405: i i word stirrup 14 406 ≧jii i word sutra 407 myf / Fig. 4 Fig. 8 Fig. 9, f7A Station B No. 10 Figure 11 2'O5

Claims (1)

[Scope of Claims] Consisting of a data transmitter and a data receiver each having a transmitting section and a receiving section, at least the data transmitter has a plurality of transmitting/receiving antennas, and from one of the antennas of the data transmitter, The data transmitter has means for determining whether an identification signal is returned from the data receiver when transmitting data, and when the identification signal is not detected, data transmission is switched to the other antenna. A diversity method that is characterized by having people do the same thing.