Radio communication system

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a technique for realizing efficient data transmission in wireless communication using a fixed-length data communication channel. For example, wireless communication stations use a TDMA / TDD system (time division multiple access / time division duplex system). The present invention relates to a technique suitable for use in a subscriber wireless access system that performs wireless communication in the system.

【0002】

[Conventional technology]

For example, a subscriber wireless access system using wireless communication called WLL (wireless local loop) or FWA (Fixed wireless access) is known. As shown in Fig. 6, for example, the subscriber wireless access system uses a TDMA / TDD system for a base station 1 fixedly installed by a telecommunications carrier and a subscriber station 2 fixedly installed on each of a plurality of users' residential areas. By wireless communication between base station 1 and subscriber station 2, data communication can be performed between LAN3s connected to different subscriber stations 2, and base stations can also be connected. Data communication with other subscriber LANs is possible via the backbone network 4 such as the public communication network connected to 1. The base station 1 accommodates a large number of subscriber stations 2, and such one-to-multipoint radio equipment is also called a P-MP (Point-Multi Point) system.

【0003】

A channel (data communication time slot) is assigned to such wireless communication between the base station 1 and the subscriber station 2, and this data communication channel is assigned to the base station under the allocation control by the base station 1. It is shared by multiple subscriber stations 2 under 1. For example, when the base station 1 and the backbone network 4 or the subscriber station 2 and the LAN 3 are connected by the wired LAN interface of Ethernet (registered trademark) and IEEE802.3, it is addressed to each subscriber terminal accommodated in the subscriber LAN3. Unicast data having individual addresses and broadcast data having addresses assigned to a plurality of subscriber terminals are transmitted and received by wireless communication between base station 1 and subscriber station 2, and a large amount of data is frequently wirelessly transmitted. Be communicated.

【0004】

Here, in a wireless communication system that employs a TDMA / TDD system wireless connection system, each subscriber station 2 may transmit / receive data (frames) only on a specific data communication channel assigned and controlled by the base station 1. The data communication channel assigned to this subscriber station 2 has a fixed length due to the nature of the TDMA / TDD system. Normally, the length of this data communication channel is set to a size that can store the maximum frame specified by Ethernet and IEEE802.3.

【0005】

[Problems to be Solved by the Invention]

However, Ethernet and IEEE 802.3 data frames that are actually transmitted and received using data communication channels have variable lengths, and since data frames of various sizes are transmitted and received, many of the data communication channels assigned to fixed lengths are used. Since the capacity was unused, efficient data transmission could not be performed, and in the end, the wireless transmission medium could not be effectively used.

【0006】

The present invention has been made in view of the above-mentioned conventional circumstances, and makes it possible to store a plurality of data frames in a fixed-length data communication channel for wireless transmission, and to make the wireless transmission medium effective by efficient data transmission. The purpose is to realize utilization. A further object of the present invention is apparent in the following description.

【0007】

[Means for solving problems]

The present invention holds a transmission target frame in at least one of a base station and a subscriber station in a wireless communication system in which wireless communication is performed between a base station and a subscriber station using a fixed-length data communication channel. The buffer is provided with a comparison means for comparing the size of the transmission target frame held in the buffer with the free size of the data communication channel, and a storage means for storing the number of transmission target frames that can be stored in the same data communication channel. ing. Therefore, in the subscriber station (or base station), a plurality of data frames are stored in the data communication channel and wirelessly transmitted, and the capacity of the data communication channel can be effectively used.

【0008】

Further, the present invention is a wireless communication device constituting a subscriber station or a base station having the above functions, whereby a wireless communication system that effectively utilizes a wireless transmission medium as described above can be realized. Further, in the present invention, a plurality of transmission target frames are stored in the same data communication channel with data indicating boundaries between frames intervening, whereby each stored in the same data communication channel on the receiving side. The frame can be easily recognized and received.

【0009】

BEST MODE FOR CARRYING OUT THE INVENTION

The wireless communication system and the wireless communication device according to the present invention will be specifically described with reference to Examples. In this example, the present invention is applied to a subscriber wireless access system (particularly, the subscriber station 2), which will be described with reference to FIG. 6 as appropriate. FIG. 1 shows the main configuration of the subscriber station 2 of this example, which is configured by applying the wireless communication device according to the present invention.

【0010】

As shown in the figure, the subscriber station 2 has the subscriber station 2 as the base station in addition to the functional parts required as a known subscriber station that performs communication processing with the subscriber LAN3 and wireless communication processing with the base station 1. A transmission processing buffer 11 that stores a plurality of transmission target frames to be wirelessly transmitted to 1 in the transmission order, a free size of a fixed-length data communication channel assigned to the own station, and a transmission target frame that is waiting for transmission and stored in the buffer 11. If there is a free size to store the transmission target frame in the fixed-length data communication channel according to the result of the comparison determination with the size determination unit 12 that compares and determines the size of A storage unit 13 is provided, and these functional units store a plurality of transmission target frames in the same data communication channel assigned to the local time station and execute a process of wirelessly transmitting from the communication unit 14.

【0011】

In this example, the transmission target frame wirelessly transmitted by the subscriber station 2 is a variable-length Ethernet and IEEE802.3 data frame, and in the figure and the following description, the transmission target frame having the first transmission order is used. The first E frame, the transmission target frame having the second transmission order is described as the second E frame, ..., and the transmission target frame having the Nth transmission order is described as the Nth E frame.

【0012】

Here, the TDMA / TDD system radio frame format used between the subscriber station 2 and the base station 1 and the data communication channel format included in the radio frame format will be described. As shown in FIG. 2, the radio frame format includes a broadcast control channel 21, a frame control channel 22, a downlink data communication channel 23, an uplink / downlink data communication channel 24, and a link control channel 25.

【0013】

The notification control channel 21 notifies the entire subordinate of the base station 1 of the synchronization establishment timing of the wireless frame, the operation information such as the frame counter and the base station identifier, and the band allocation information of the data communication channel. The frame control channel 22 notifies the band allocation information of the link control channel 25, and the authentication result information of the subscriber station in the base station and the subscriber terminals under it. The downlink data communication channel 23 transmits an Ethernet data frame from the base station to the subscriber station.

【0014】

The uplink / downlink data communication channel 24 transmits Ethernet data frames from the base station to the subscriber station or from the subscriber station to the base station. The link control channel 25 transmits a radio band allocation request to a base station that uses the uplink / downlink data communication channel 24 for uplink data communication, and transmits an authentication request from the subscriber station to the base station. That is, the base station 2 stores the data frame to be transmitted held in the buffer 11 in the uplink / downlink data communication channel 24 and wirelessly transmits the data frame to the base station 1.

【0015】

The data communication channel 24 included in the wireless frame format has a fixed length, and as shown in FIG. 3, the data communication channel format includes a bit synchronization signal unit 31 for establishing bit synchronization and a frame for establishing frame synchronization. Stores the synchronization signal unit 32, the channel identification signal unit 33 for identifying the channel, the wireless subscriber station identifier unit 34 for identifying the assigned subscriber station, and the data frame to be transmitted wirelessly transmitted by the subscriber station. It includes a data signal unit 35 and an error detection code unit 36 for error detection. That is, the transmission target data frames (first E frame, second E frame, ... Nth E frame) held in the buffer 11 are stored in the fixed-length data signal unit 35 and wirelessly transmitted.

【0016】

Next, the transmission process according to the above configuration will be described. FIG. 4 shows a procedure for storing the data frame to be transmitted in the fixed-length data signal unit 35 performed by the subscriber station 2. First, in the subscriber station 2, when data frames to be wirelessly transmitted to the base station 1 are generated, these are sequentially held in the buffer 11. Then, when the data frame is stored in the buffer 11, the storage unit 13 takes out the data frame (first E frame) stored in the buffer 11 first and stores it in the data signal unit 35 of the data communication channel 24 ( Step S1).

【0017】

Next, the size determination unit 12 takes out the data frame (second E frame) stored in the buffer 11 and compares it with the free size of the data signal unit 35 storing the first E frame (step S2). As a result, if there is a free size that can store this second E frame, the storage unit 13 inserts a delimiter bit indicating the boundary between the first E frame and the second E frame as shown in FIG. (Step S3), the second E frame is stored in the same data signal unit 35 as the first E frame (step S4).

【0018】

Further, the size determination unit 12 then takes out the data frame (third E frame) stored in the buffer 11 and compares it with the free size of the data signal unit 35 storing the first E frame and the second E frame. (Step S5) If there is a free size that can store the 3rd E frame, the storage unit 13 inserts a delimiter bit indicating the boundary between the 2nd E frame and the 3rd E frame as shown in FIG. Then (step S6), the third E frame is stored in the same data signal unit 35 as the first E frame and the second E frame (step S7).

【0019】

In this way, if the fixed-length data signal unit 35 has a free size for storing the next E frame, the process of storing this in the same data signal unit 35 is performed, and the free size data for storing the next E frame is performed. When the signal unit 35 disappears, the communication unit 14 wirelessly transmits the data to the base station 1 (step S8). Here, in the actual TDMA / TDD method, since the data communication channel is transmitted in units of a fixed cycle, the above-mentioned storage process is performed during the transmission cycle, and the storage process may cause a transmission delay. Absent.

【0020】

Although the above embodiment has been described by taking the subscriber station 2 as an example, the present invention can be applied to the base station 1 in the same manner, and the effective use of the wireless communication medium can be similarly achieved. Further, the present invention is not limited to the subscriber wireless access system, and is not limited to the TDMA / TDD system, and can be widely used for wireless communication using a fixed-length data communication channel. Similarly, wireless communication can be used. Effective use of media can be achieved.

【0021】

[Effect of the invention]

As described above, according to the present invention, wireless communication can be efficiently performed by efficiently using a fixed-length data communication channel, and a wireless communication medium can be effectively utilized. In particular, in a subscriber wireless access system that can use only a fairly narrow band such as quasi-millimeter wave or millimeter wave, such a limited wireless communication medium is effectively utilized to accommodate a subscriber station per base station. Can be increased to provide sufficient communication services.

[Simple explanation of drawings]

[Figure 1]

It is a block diagram of the main part of the subscriber station which concerns on one Example of this invention.

[Figure 2]

It is a figure which shows the radio frame format which concerns on one Example of this invention.

[Fig. 3]

It is a figure which shows the data communication channel format which concerns on one Example of this invention.

[Fig. 4]

It is a flowchart which shows the transmission treatment procedure which concerns on one Example of this invention.

[Fig. 5]

It is a figure explaining the storage state of the transmission target data frame which concerns on one Example of this invention.

[Fig. 6]

It is a figure which shows an example of a subscriber wireless access system.

[Explanation of symbols]

1: Base station, 2: Subscriber station, 11: Buffer, 12: Size determination unit, 13: Storage unit, 23, 24: Data communication channel, 35: Data signal unit,