JP2531380B2 - Wireless TDD transmission 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 time division multiplex (TDD) transmission system, and more particularly to a time division multiple access (TDMA) -TD.
The present invention relates to a wireless LAN communication device in which a D-type wireless communication device and a wired LAN are connected to perform packet communication with each other.

[0002]

2. Description of the Related Art As a wireless communication system of this kind of TDMA-TDD system, various systems are known in addition to being disclosed in, for example, Japanese Patent Laid-Open No. 4-373321. As an example, a wireless TD used as a wireless LAN communication device
The D transmission method will be described with reference to FIG.

In FIG. 5, a wireless LAN device is composed of a wireless master station 100 and a plurality of wireless slave stations 201 and 202, and is further connected to a plurality of wired slave stations 301 and 302 by a wired LAN 300. In this wireless line, the wireless master station 100 to the wireless slave stations 201 and 202
The transmission directed to the wireless slave station 201, 202 is referred to as "downlink", and the transmission directed to the wireless master station 100 is referred to as "uplink".

The radio master station 100 emits radio waves into the air from the antenna 130 and captures radio waves from the air in order to perform wireless communication with the radio slave station 201 or the radio slave station 202. . The transmission signal to the antenna 130 and the reception signal from the antenna 130 are switched by the antenna transmission / reception switching circuit 101. This switching is controlled by the switching control signal generated by the switching control circuit 115 so as to switch one wireless TDD frame at the time intervals determined for transmission and reception. A reception signal in the radio frequency band from the antenna transmission / reception switching circuit 101 is input to the receiver 102 and converted into baseband reception data. The wireless packet data processing unit 128 receives the demodulated received data, analyzes each wireless packet sent from each wireless slave station, and extracts transmission data, packet control information, and reservation information for a wireless TDD frame. Output them.

The transmission data for each packet from the wireless packet data processing unit 128 is determined by the data switching circuit 110 according to the destination information (transmission address) of the wireless packet data processing unit 128 to be a wireless slave station or a wired slave station. , Which are sent to the wireless packet assembling unit 116 and those which are sent to the wired packet assembling unit 119. The transmission data sent to the wired packet assembling unit 119 is reconfigured as a new wired packet together with the packet control information from the wireless packet data processing unit 128 and sent to the wired packet network interface 120.

On the other hand, the wireless master station 100 has an external wired L
A wired packet network interface 120 is provided to connect to the AN 300 and send and receive wired packets. The wired packet data processing unit 129 decodes the wired packet received from the wired packet network interface 120, extracts transmission data and control information of the packet, and outputs the data and information.

The transmission data sent to the wireless packet assembling unit 116 is reconstructed as a new wireless packet together with the packet control information from the wireless packet data processing unit 128, and sent to the wireless TDD frame assembling unit 117. The wireless packet assembling unit 116 also receives the transmission data and the packet control information from the wired packet data processing unit 129 and reconstructs a new wireless packet. The generated wireless packet is inserted into the transmission time slot of the wireless TDD frame by the wireless TDD frame assembling unit 117. Further, some wireless slave stations are assigned to the reception time slot of the wireless TDD frame. Therefore, the wireless packet data processing unit 1
Based on the time slot reservation information from 28, the transmission permission information creating unit 114 determines the time slot allocation position and the number of allocation slots, and sends this allocation slot information to the wireless TDD frame assembling unit 117. Wireless T
The DD frame assembling unit 117 puts this allocation slot information on the wireless TDD frame and configures the wireless TDD frame together with the downlink wireless packet. This is passed to the transmitter 118 and converted into a transmission signal in the radio frequency band.

Here, the wireless packet data processing unit 128
Is a reservation packet for receiving the received data from the receiver 102 and making a time slot allocation request for transmission from the wireless slave station, or transmitting data from the wireless slave station. It has a packet attribute decoding unit 103 that determines the packet attribute as to whether it is a data packet to be included and extracts the reservation information of the packet. The wireless packet data processing unit 128 further decodes the information indicating the transmission source of the packet and outputs it.
04, a reception address decoding unit 105 that decodes and outputs the information indicating the destination of the packet, and a user data separation unit 106 that extracts and outputs the transmission data of the data packet.
And a receiving side memory 109 for temporarily storing the transmission data from the user data separating section 106 for each transmission source, the packet attribute decoding section 103, the transmission address decoding section 104 and the reception address decoding section 105. It has a packet information management unit 107 that manages packet reservation information and control information and outputs necessary information to the outside.

Also, the wired packet data processing unit 129
Is a transmission address decoding unit 121 that receives a wired packet from the wired packet network interface 120, decodes and outputs information indicating the transmission source of the packet, and a reception address decoding unit that decodes and outputs information indicating the destination of the packet. Unit 122, user data separation unit 123 that extracts and outputs packet transmission data, transmission side memory 127 for temporarily storing transmission data from user data separation unit 123 for each transmission source, and transmission address decoding unit 12
1 and a packet information management unit 124 which manages the control information of each packet passed from the reception address decoding unit 122 and outputs necessary information to the outside.

FIG. 6 shows an example of a signal format of a wireless TDD frame in the wireless TDD transmission system. In either case, the wireless TDD frame includes a wireless TDD frame synchronization control unit including a frame synchronization bit for synchronizing with a frame from the wireless master station in the wireless slave station, and uplink / downlink allocated time slot information and transmission. A frame information slot that carries information such as the length of downlink data that is being transmitted, a downlink data time slot for transmitting data from the wireless master station to the wireless slave station, and data from the wireless slave station to the wireless master station. It is used to request allocation of the uplink data time slot for transmitting data and the uplink data time slot for the wireless mobile station to transmit data in the upstream direction. It is composed of slots and. Here, a guard bit, which is a blank time necessary for separating transmission and reception, is set between the downlink data time slot and the uplink data time slot. Therefore, in the wireless master station, the operation of transmission and reception is switched in the frame with this guard bit as a boundary.

In such a wireless TDD frame,
Conventionally, the number of downlink and uplink data time slots is fixed for a frame. In this example, 15
The slot and its downlink / uplink ratio is 1: 1. Here, there are five wireless slave stations 1 to 5, the wireless slave station 2 has 3 slots for the downlink traffic amount, the wireless slave station 4 has 5 slots, and the others are 0, and the upstream traffic amount is the wireless slave station. 1 has 4 slots, wireless slave station 2 has 5 slots, wireless slave station 5 has 8 slots, and others have 0 slots. With such a fixed duty, even though there are 7 empty slots in the downlink, the uplink traffic cannot be completely transmitted only in this frame, and 2 slots must be sent to the next frame.

[0012]

As described above, according to the conventional wireless TDD transmission method, the duty of the upstream time slot and the downstream time slot of the wireless TDD frame is irrespective of the amount of upstream and downstream transmission traffic on the wireless circuit. The ratio is fixed. Therefore, when the amount of transmission traffic greatly differs between upstream and downstream, the frequency of occurrence of empty slots in the wireless TDD frame increases, the use efficiency of time slots decreases, and the transmission time is also proportional to the amount of transmission traffic. There was a problem that it increased. Further, since the empty slot in the wireless TDD frame is not used until the transmission data is assigned, the wireless TDD frame has not been effectively used.

Therefore, a main object of the present invention is to provide a wireless TDD transmission system capable of arbitrarily changing the duty ratio of transmission and reception.

Another object of the present invention is to provide a wireless TDD transmission system which suppresses the occurrence of empty slots as much as possible and can be used for another purpose when the empty slots occur.

[0015]

According to the present invention, a plurality of wireless slave stations are provided for one wireless master station, and the wireless master station is connected to a wired packet communication network having a plurality of wired slave stations. A wireless transmission system of a TDMA-TDD system that also performs packet transmission between a wireless slave station and the wired slave station, wherein the wireless master station has a time interval according to a duty ratio of transmission and reception. A switching control circuit for transmitting a switching control signal for switching between transmission and reception, and some wireless packets included in a wireless TDD frame of data obtained by demodulating a received signal from the wireless slave station. Wireless packet data processing unit that sequentially identifies the respective attributes from each other to extract control information, reservation information, and transmission data for each wireless packet, and a wired packet network interface connected to the wired packet communication network. A wired packet data processing unit for extracting control information and transmission data of a wired packet received through the interface, and an upward direction from a wireless slave station to a wireless master station in a wireless TDD frame based on reservation information from the wireless packet data processing unit. Wireless TDD including a transmission permission information creation unit that determines an allocation position and a number of allocation slots of a wireless slave station that uses a time slot for transmission of
In a transmission method, a data length of a packet transmitted in an upward direction from a wireless slave station extracted by the wireless packet data processing unit is measured and reception data length information is output.
And a second data length calculation unit for measuring the transmission data extracted from the wired packet in the wired packet data processing unit and outputting the received data length information, and the two received data length information. A downlink data amount integrating unit that calculates the total amount of data to be transmitted in the downlink direction by adding up all the packets received and transmitted to the wireless master station, and a packet reservation detected in the wireless packet data processing unit An upstream data amount integrating unit for calculating the total amount of data to be transmitted in the upstream direction by the wireless mobile station from the transmission data length obtained from the information and the received data length of the packet transmitted in the upstream direction; and the downlink data amount integration Of the radio frame by receiving the downlink data total amount information from the unit and the uplink data total amount information from the uplink data amount integrating unit. Time ratio assigned respectively to receive the signal, characterized in that a duty determination unit for sending the duty control information to the transmission permission information creation unit and the switching control circuit determines (duty ratio).

According to the present invention, the wireless master station further assembles a wireless packet that constitutes transmission data to the wireless slave station from transmission data extracted from a wireless packet or a wired packet and packet control information. An assembling unit, and a wired packet assembling unit for assembling a wired packet from the transfer data and packet control information extracted by the wireless packet data processing unit so as to put the wireless packet data from the wireless slave station on the wired packet communication network. Whether the received data extracted by the wireless packet data processing unit is sent to the wireless packet assembling unit as transmission data in the wireless network downlink direction or is sent to the wired packet assembling unit as transmission data to be sent to the wired packet communication network. Data switching for determining data from the packet control information to switch data A wireless TDD frame from a path, a wireless packet for the downlink transmission from the wireless master station to the wireless slave station from the wireless packet assembling section, and upstream time slot allocation information from the transmission permission information creating section. A wireless TDD frame assembling unit for assembling, and further, obtains allocation slot information of the current wireless slave station for the upstream time slot of the wireless TDD frame from the transmission permission information creating unit, and still allocates to the wireless slave station by reservation. A reserved slot determining unit for generating allocation information to be inserted into the wireless TDD frame by the wireless TDD frame assembling unit in order to allocate an unused reserved slot as an additional reserved slot common to the wireless slave stations. A wireless TDD transmission method is obtained.

The radio master station further counts the reservation frequency of each radio slave station within a certain period and allocates the reservation frequency information to allocate the extension reservation slot as a dedicated reservation slot of a radio slave station having a high reservation frequency. It is preferable to include a reservation frequency counting unit for outputting.

[0018]

Next, the present invention will be described with reference to the drawings. 1 is a block diagram of an embodiment of the present invention.
The same parts as those in FIG. 5 are designated by the same reference numerals and the description thereof will be omitted. In FIG. 1, the operation of the functional blocks added to the configuration of FIG. 5 will be described in detail below.

First, the data length calculation unit 108 (first data length calculation unit) on the radio packet data processing unit 128 side
The transmission data of each wireless packet is received from the wireless packet data processing unit 128, the received data length is calculated, and this received data length information is used as the downlink data amount integration unit 126 and the packet information management unit 1 in the wireless packet data processing unit 128.
It is sending to 07. Wired packet data processing unit 129
Side data length calculation unit 125 (second data length calculation unit)
Receives the transmission data of the wired packet from the wired packet data processing unit 129, calculates the received data length,
This received data length information is sent to the downlink data amount integration unit 126 and the packet information management unit 124 in the wired packet data processing unit 129. In the downlink data amount integration unit 126, the received data length information of the wireless packet from the data length calculation unit 108, the packet control information from the packet information management unit 107 in the wireless packet data processing unit 128, and the data length calculation unit 125 Of the received data length information of the wired packet and the packet control information from the packet information management unit 124 in the wireless packet data processing unit 128, the data to be transmitted in the wireless downlink direction is identified, the total amount of the data is calculated, and the duty is calculated. Information on the total amount of downlink data is sent to the determination unit 112.

In the upstream data amount integrating unit 111, the packet attribute decoding unit 103 in the wireless packet data processing unit 128 is provided.
From the packet information management unit 1
From 07, the information of the already transmitted data length is received from the reserved wireless slave station, the total amount of data scheduled to be transmitted by the wireless slave station in the upstream direction is calculated, and the information is transmitted to the duty determining unit 112. are doing. The duty determining unit 112 determines the ratio of the time slots assigned to transmission (downlink) and reception (uplink) in the wireless TDD frame according to the ratio of this data amount from the information on the total amount of uplink data and the information on the total amount of downlink data. A certain duty ratio is determined, and this duty information is used as the reservation slot determination unit 1
13, transmission permission information creation unit 114, and switching control circuit 115
And sent to. As a result, more time slots of the wireless TDD frame are allocated to the direction in which the amount of transmission traffic to be transmitted is larger, and the total processing time required to transmit the entire amount of upstream and downstream traffic. Will be shortened.

FIG. 2 is a signal format of a wireless TDD frame of the wireless TDD transmission system in the case of the variable duty ratio of the present invention. Here, the reservation slot is a common time slot for transmitting reservation information for requesting allocation of an uplink data time slot from each radio slave station to the radio master station, and the expansion reservation slot is an uplink This is a time slot in which an empty slot with no transmission data is assigned as a reservation slot in the data time slot. The frame information slot is a time slot for carrying duty information, uplink allocated time slot information, downlink allocated time slot information, and the number of wireless packets scheduled to be transmitted to each wireless slave station.
The frame synchronization control unit is a time slot for carrying a frame synchronization bit and the like.

In the case of such a variable duty, the ratio of the total downlink traffic and the total uplink traffic is calculated at the time of frame assembly (here, the total downlink traffic = 8 slots, whereas the total uplink traffic = 17 slots, the duty ratio 1 : 2), the data time slot is divided into upstream and downstream by this duty ratio. As a result, there are only two empty slots in the downlink, and all traffic can be transmitted in this frame once in the uplink.

At this time, three vacant slots are also generated in the uplink, but by allocating these vacant slots as additional reserved slots, the probability of data collision between wireless slave stations in the reserved slots can be reduced. Therefore, the reserved slot determination unit 113 is provided, and the duty information from the duty determination unit 112 and the allocation slot information for the wireless slave station from the transmission permission information generation unit 114 can be received and used as reserved slots for empty slots. And assign information to this empty slot to the wireless TD.
It is sent to the D frame assembly section 117. Further, if this additional reserved slot is allocated in the wireless TDD frame as a reserved slot dedicated to a specific wireless slave station, apart from the reserved slot common to all normal wireless slave stations, the dedicated reserved slot The wireless slave station to which is allocated does not have a collision with a reservation packet from another wireless slave station when the reservation packet is transmitted. Therefore, there is no need for retransmission, and the transmission throughput is improved.
When allocating this dedicated reserved slot to a specific wireless slave station, in order to obtain the greatest possible improvement in throughput, wireless slave stations with the highest frequency of reservation are allocated in order, so a reserved packet is generated for each wireless slave station. It has a reservation frequency counting unit 131 that counts frequencies and outputs the information.

3 and 4 are flowcharts showing the procedure of transmitting and receiving the wireless TDD frame in the above-described wireless master station, which is executed in the following steps.

Upper / lower time slot number setting The duty determining unit 112 obtains duty information and determines the number of up and down time slots from this duty information.

Downlink slot allocation / writing of transmission data Downlink data allocation slots are determined, downlink allocation slot information is loaded in the frame information slot, and transmission data is loaded in the downlink data allocation slot.

Uplink slot allocation Uplink time slots are allocated to wireless slave stations that have made reservation requests, and upstream allocation slot information is placed in frame information slots.

Expansion reserved slot setting A judgment operation is performed as to whether or not there is an unallocated slot in the upstream data time slot, and if there is not, the process proceeds to the next step, and if there is, an expansion reserved slot information is placed in the frame information slot.

Acquisition of reservation information of reserved slot Read information of reserved slot, determine whether or not there is an allocation request in the reserved slot, read information of reserved slot if there is, move to next step if not To do.

Acquisition of Reservation Information for Expansion Reserved Slots First, an operation for determining whether or not there is an expansion reserved slot is performed. If there is no expansion reserved slot, the process proceeds to the next step. On the other hand, if there is an expansion reserved slot, the data in the expansion reserved slot is read, the operation to determine whether or not there is an allocation request in the expansion reserved slot is performed, and if there is, the information in the expansion reserved slot is read again. If so, move to the next step.

Reading Upstream Data A determination operation is performed as to whether there is upstream data that has not been read out. If there is, the next data is read from the upstream data time slot, the wireless packet from the wireless slave station is decoded, and the above determination is performed again. Take action. If there is no upstream data, the process moves to the next frame.

[0032]

As described above, according to the present invention, the wireless T
By making it possible to change the up and down duty ratio of the time slot in the DD frame according to the up and down transmission traffic volume, the wireless TDD frame can be efficiently used so as to avoid creating empty slots as much as possible. it can. As a result, there is an effect that the throughput of traffic in the wireless TDD section can be improved. Also, when an empty slot occurs, by assigning it as a reserved slot of the wireless slave station,
The connection rate from the wireless slave station is improved, which allows wireless TD
There is an effect that the traffic throughput in the D section is further improved.

[Brief description of drawings]

FIG. 1 is a block diagram of a wireless LAN device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a signal format of a wireless TDD frame according to the present invention.

FIG. 3 is a flowchart showing a part of a transmission / reception procedure of a wireless TDD frame in a wireless master station according to the present invention.

FIG. 4 is a flowchart showing a procedure of transmitting / receiving a wireless TDD frame in the wireless master station, following FIG. 3;

FIG. 5 is a block diagram of a conventional wireless LAN device of a wireless TDD transmission system.

FIG. 6 is a diagram showing an example of a signal format of a conventional wireless TDD frame.

[Explanation of symbols]

 100 wireless master station 101 antenna transmission / reception switching circuit 102 receiver 108, 125 data length calculation unit 110 data switching circuit 111 upstream data amount integration unit 112 duty determination unit 113 reserved slot determination unit 114 transmission permission information generation unit 115 switching control circuit 116 wireless Packet assembling unit 117 Wireless TDD frame assembling unit 118 Transmitter 119 Wired packet assembling unit 120 Wired packet network interface 126 Downstream data amount accumulating unit 127 Transmitting side memory 128 Wireless packet data processing unit 129 Wired packet data processing unit 130 Antenna 131 Reservation frequency counting Part 201, 202 Wireless slave station 300 Wired LAN 301, 302 Wired slave station

Claims (3)

(57) [Claims] 1. A wireless slave station and a wired slave station having a plurality of wireless slave stations for one wireless master station, the wireless master station being connected to a wired packet communication network having a plurality of wired slave stations. TDMA-TDD for packet transmission to and from
A wireless master station, wherein the wireless master station sends a switching control signal for switching between transmission and reception at respective time intervals according to a duty ratio of transmission and reception; Each attribute is sequentially identified from several wireless packets included in a wireless TDD frame of data obtained by demodulating a received signal from a wireless slave station, and control information, reservation information, and transmission are performed for each wireless packet. A wireless packet data processing unit for extracting data, a wired packet data processing unit for extracting control information and transmission data of a wired packet received through a wired packet network interface connected to the wired packet communication network, and the wireless packet data processing unit Wireless TDD based on reservation information from
Radio TDD transmission including a transmission permission information creating unit that determines an allocation position and a number of allocated slots of a wireless slave station that uses a time slot for upstream transmission from a wireless slave station in a frame to a wireless master station In the method, a first data length calculation unit that measures a data length in a packet transmitted in the upstream direction from the wireless slave station extracted by the wireless packet data processing unit and outputs received data length information; A second data length calculation unit that measures transmission data extracted from a wired packet in a packet data processing unit and outputs reception data length information; and a second data length calculation unit that receives the two reception data length information and sends the reception data length information to the wireless master station. A downlink data amount integrating unit for calculating a total amount of data to be transmitted in the downlink direction by adding up all transmitted packets, and the wireless packet. Upstream data for calculating the total amount of data scheduled to be transmitted by the wireless slave station in the upstream direction from the transmission data length obtained from the packet reservation information detected in the data processing unit and the received data length of the packet transmitted in the upstream direction. A time ratio (duty ratio) assigned to each of the amount integration unit, the downlink data amount integration unit from the downlink data amount integration unit, and the uplink data amount information from the uplink data amount integration unit to transmit and receive a radio frame. Ratio), and a duty determination section for transmitting the duty control information to the transmission control information generating section and the switching control circuit. 2. The wireless TDD transmission system according to claim 1, wherein the wireless master station further configures transmission data to the wireless slave station from transmission data extracted from a wireless packet or a wired packet and packet control information. A wireless packet assembling unit for assembling a wireless packet and a wired packet from the transfer data and packet control information extracted by the wireless packet data processing unit for loading the wireless packet data from the wireless slave station on the wired packet communication network. The wired packet assembling unit to be assembled and the received data extracted by the wireless packet data processing unit are sent to the wireless packet assembling unit as transmission data in the wireless network downlink direction, or the wired data is transmitted as transmission data to be sent to the wired packet communication network. It is judged whether to send to the packet assembling unit from the packet control information, and the data A data switching circuit for switching, a radio packet for transmission from the radio packet assembling unit in the downlink direction from the radio master station to the radio slave station, and uplink time slot allocation information from the transmission permission information creating unit. And a wireless TDD frame assembling unit for assembling a wireless TDD frame from, and obtaining the allocation slot information of the current wireless slave station for the upstream time slot of the wireless TDD frame from the transmission permission information creating unit, and still by reservation. Reserved slot for generating allocation information to be inserted into the wireless TDD frame by the wireless TDD frame assembling unit for allocating as an additional reserved slot common to the wireless slave station to an empty slot not allocated to the wireless slave station. A wireless TDD transmission method comprising a determination unit. 3. The wireless TDD transmission method according to claim 2, wherein the wireless master station further allocates the additional reserved slot as a dedicated reserved slot for a wireless slave station having a high frequency of reservation, so that each wireless communication within a certain period of time is performed. A wireless TDD transmission system comprising a reservation frequency counting unit for counting the reservation frequency of a slave station and outputting the reservation frequency information.