JPH11285061A - Radio transmitting and receiving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an interference evading function and to freely set transmission capacity for respective terminals by using different multiplexing methods which are different in signal property and demanded quality correspondence to signals for plural burst signals having mutually different properties. SOLUTION: A terminal station establishes frame synchronism by receiving a time-division-multiplex TDMA applied access segment ASG used for frame synchronization in addition to information notification, controls transmit power by performing the code spreading of a Cch signal including a data request-to- send signal and an answer signal for base station calling, etc., multiplexes incoming and outgoing burst signals by TDMA, and transmits them to a control segment CSG having a constant information transmission rate with transmit power less than the USG signal power of a user segment whose information transmission rate can freely be set. The control signal of a base station is extracted by the reverse spreading of the Cch signal. The allocation of the USGs is controlled with information transmitted and received between the CGSs and a burst signal is sent to a specified position in the USG.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio transmission / reception method for transmitting / receiving a signal through a radio channel on the same frequency channel.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a conventional method for transmitting and receiving a radio signal on the same frequency channel. In this conventional example, in a centralized control type system including one base station and one or a plurality of (≧ 1) terminal stations, TDMA (TDMA) is used as a method for transmitting and receiving signals over a radio channel on the same frequency channel. Time-division multiple access).

As shown in FIG. 1, a base station to which a certain frequency channel is assigned forms a frame of a fixed length on that frequency channel. This frame includes an access segment (ASG) that broadcasts information on the radio base station,
It is divided into a plurality of segments according to the characteristics of the signal, such as a control segment (CSG) for transmitting and receiving a radio channel control information signal between a base station and a terminal station and a user segment (USG) for transmitting and receiving a data signal. ing. Further, a plurality of channels are time-division multiplexed on each segment. The actual signal is transmitted and received using one of the channels in the segment, which is assigned by the base station.

[0004]

In an environment where there are a plurality of base station zones using the same frequency channel, when such a conventional signal transmission / reception method is used, a signal may be generated due to interference from other zones. Normal reception is no longer possible. For this reason, the base station must control channel assignment so that channels used in other zones are not used. At this time, the function of the signal of each segment is different. For example, since ASG and CSG in FIG. 4 are used for control, the requirements for quality are stricter than USG used for data signal transmission.

Therefore, in the conventional method, as shown in FIG. 4, the same frequency channel is used by shifting the frame start timing so that the ASG and the CSG do not interfere with each other, and the USG interferes with the ASG and the CSG. Channels are allocated not to give. However, according to this method, since the ASG is used for reporting information and is always transmitted in all directions, Uch in the USG at the same timing as the ASG transmitted from another base station is:
It cannot be used at all times. Also, the USG at the same timing as the CSG Cch signal used in another base station is used.
Uch in SG has a high probability of becoming unusable as the number of users increases.

In other words, since the ASG is constantly transmitted from another base station, if a Uch signal transmitted at the same timing as the ASG of the other base station is used, interference occurs in the ASG of the other base station. It can not be used because it will be. In addition, as the number of users accommodated in other base stations of the CSG increases, the number of Cch's transmitted increases. Since Uch at the same timing cannot be used in order not to interfere with Cch, the number of unusable Uch increases as the number of users increases.

For the above reasons, in the conventional method,
When another base station using the same frequency channel is present in the vicinity, the allocation of the low-priority segments is restricted by the high-priority segments. as a result,
In the conventional example shown in FIG. 4, the effective transmission capacity decreases.

[0008] CDMA (code division multiple access) is generally known as a multiplexing method that is resistant to interference from other sources. In CDMA, a signal is spread according to a user-specific spreading code, and a plurality of users are multiplexed using the spreading code. Here, the control signal of each user terminal is multiplexed by transmitting the control information during the CSG while keeping the signal speed after spreading. By using this CDMA, the anti-interference characteristics are improved.

However, according to CDMA, the transmission rate is determined in code units. In TDMA, however, the transmission capacity for each terminal can be freely changed by changing the time allocation. Can only be changed in code units.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a radio transmission / reception method which has an excellent interference avoidance function and can freely set a transmission capacity for each terminal.

[0011]

In the frame structure as shown in FIG. 4, the ASG and CSG generally handle control information, so that the requirements for transmission quality are severe, but the transmission capacity is always constant. On the other hand, USG, which transmits and receives data, is controlled in such a manner that the transmission capacity of each terminal changes with time, especially in a network with variable traffic such as LAN, but the quality is kept constant by ARQ or the like. However, the requirements for transmission quality are lower than for control signals. As described above, the requirements for transmission quality and transmission capacity are different depending on each segment.

Therefore, according to the present invention, a radio transmission / reception which has solved the above-mentioned problems by adopting different multiplexing methods for a plurality of burst signals having different properties according to the properties of the signals and the required quality of the signals. A method is provided. Further, according to the present invention, in a system in which a segment is divided like a control signal and a data signal, code division multiplexing (CD) having excellent interference resistance characteristics with respect to the control signal is performed.
A wireless transmission / reception method for performing transmission / reception using time division multiplexing (TDMA) that can easily change the transmission capacity of the data signal segment for the data signal segment is provided.

In the latter case, it is preferable to transmit a signal of a segment to be transmitted using CDMA with a lower transmission power than in the case of another segment in order to reduce interference with other segments.

[0014]

FIG. 1 is a diagram showing a method for transmitting and receiving a radio signal according to an embodiment of the present invention. Also in the present embodiment, the frame is an access segment (ASG) that broadcasts information on the radio base station, and a radio channel control information signal between the base station and the terminal station, as in the case of the conventional technique shown in FIG. Control segment (CSG) for transmitting and receiving data and user segment (USG) for transmitting and receiving data signals
Is composed of multiple segments.

As is apparent from FIG. 1, in the system of the present embodiment, the USG uses an uplink signal (from a terminal station to a base station) and a downlink signal using TDMA so that the information transmission rate can be freely set. Each burst signal of a signal (base station → terminal station) is multiplexed. In CSG, since the information transmission rate is always constant and the quality must be kept high even when interference from other base stations is added, each control signal is multiplexed using CDMA.

In order to make the bandwidth occupied by the TDMA segment and the CDMA segment the same, if the CDMA spreading code length is n and the signal transmission speed in the TDMA section is F, the information transmission rate in the CDMA section is F / n or less. The spreading code length is determined according to the number of channels in the CSG and the information transmission speed. Note that ASG is used for synchronizing frames in addition to reporting information, so TDMA is applied.

FIG. 2 is a block diagram showing a configuration example of a terminal station in the present embodiment. In the figure, 1 is a terminal station antenna, 2 is a TDD-SW, 3 is a receiver, 4 is a demodulator, 5 is a signal distribution circuit, 6 is a spectrum despreader, 7 is a transmitter, 8 is a modulator, 9 Denotes a signal multiplexing circuit, 10 denotes a spectrum spreader, and 11 denotes a terminal station transmission / reception control circuit. Further, D is a system information and downlink data signal output, E is a downlink control signal output, F is an uplink data signal input, G is an uplink control signal input, H is a transmission-reception switching timing signal, K is a transmission power control signal, and L is a transmission power control signal. Denotes a segment switching signal, M denotes a terminal station timing control signal, and N denotes an uplink data signal output.

The terminal station receives the ASG,
Establish frame synchronization, code-spread a Cch signal including a data transmission request signal, a response signal to a call from a base station, and control the transmission power.
Is transmitted at a transmission power lower than the signal power. Control information from the base station is extracted by receiving a Cch signal and despreading the signal. Then, the allocation of the USG is controlled using the information exchanged in the CSG section, and the burst signal is transmitted to the designated position in the USG.

FIG. 3 is a block diagram showing a configuration example of the base station in the present embodiment. In the figure, 21 is a base station antenna, 22 is a TDD-SW, 23 is a receiver, 24
Is a demodulator, 25 is a signal distribution circuit, 26-1 to 26-x are base station spectrum despreaders, 27 is a transmitter, 28 is a modulator, 29 is a signal multiplexing circuit, and 30-1 to 30-x are spectrums. A spreader, 31 indicates a base station transmission / reception control circuit, and 32 indicates a signal combining circuit. Further, N is an uplink data signal output, P-1 to Px are uplink control signal outputs, Q is system information and downlink data signal input, and R-1 to Rx.
Is a downlink control signal input, H is a transmission-reception switching timing signal, K is a transmission power control signal, L is a segment switching signal,
S indicates a base station timing control signal.

The base station transmits an ASG burst signal at regular intervals. In the CSG, a code-spread Cch signal is input from a plurality of terminal stations, and the Cch signal is despread with a plurality of spreading codes corresponding to the code of each terminal to identify a control signal sent from each terminal. . Further, control signals such as a band allocation to each terminal station and a paging signal are spread by a code according to the terminal station, and transmitted after being combined with each other. At this time, the transmission power is controlled according to the number of Cch signals to be transmitted. The data signal transmits and receives a Uch burst signal to and from a predetermined position in the USG.

The embodiments described above are merely examples of the present invention, and do not limit the present invention. The present invention can be embodied in other various modifications and alterations. Therefore, the scope of the present invention is defined only by the appended claims and their equivalents.

[0022]

As described above in detail, according to the present invention, when one or more burst signals having different characteristics exist, different multiplexing methods depending on the characteristics of the signal and the required quality of the signal are used. Multiplexed transmission and reception
As a specific example, since CDMA is used for transmitting control information and TDMA is used for transmitting data signals, it is possible to maintain the transmission quality of control information even when receiving interference from TDMA signals in other zones. It becomes possible. Also, CDM
Since the transmission power of the A signal can be reduced, the amount of interference with the TDMA signal in another zone can be reduced. As a result, the probability that the data transmission channel can be used increases, and it is possible to prevent a reduction in transmission capacity.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a wireless signal transmission / reception method according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration example of a terminal station according to the present embodiment.

FIG. 3 is a block diagram illustrating a configuration example of a base station according to the present embodiment.

FIG. 4 is a diagram for explaining a frame configuration and a deterioration in transmission capacity according to a conventional method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Terminal station antenna 2, 22 TDD-SW 3, 23 Receiver 4, 24 Demodulator 5, 25 Signal distribution circuit 6, 26-1 to 26-x Spectrum despreader 7, 27 Transmitter 8, 28 Modulator 9 , 29 signal multiplexing circuit 10, 30-1 to 30-x spectrum spreader 11 terminal station transmission / reception control circuit 21 base station antenna 31 base station transmission / reception control circuit 32 signal combining circuit A access channel B1 code-multiplexed control channel signal B2 Divided and multiplexed control channel signal C User channel signal D System information and downlink data signal output E Downlink control signal output F Uplink data signal input G Uplink control signal input H Transmission-reception switching timing signal K Transmission power control signal L Segment switching signal M terminal station timing control signal N uplink data signal output P-1 to Px uplink control Signal output Q System information and downlink data signal input R-1 to Rx Downlink control signal input S Base station timing control signal

Claims (3)

[Claims] 1. A wireless transmission / reception method in a system including one base station and one or more terminal stations for transmitting / receiving a signal through a wireless channel on the same frequency channel,
A wireless transmission / reception method, wherein a plurality of burst signals having different properties are multiplexed and transmitted / received by different multiplexing methods corresponding to the properties of the signals. 2. A wireless transmission / reception method in a system comprising one base station and one or more terminal stations, wherein signals are transmitted / received on a radio line on the same frequency channel which is time-divided into a plurality of segments. In a segment for transmitting and receiving line control information with the one or more terminal stations, a code-multiplexed signal is transmitted and received, and in a segment for transmitting and receiving data signals, a time-division multiplexed signal is transmitted and received. Characteristic wireless transmission / reception method. 3. The radio according to claim 2, wherein when transmitting a signal to a segment for transmitting and receiving a code-multiplexed signal, transmission is performed with lower transmission power than in other segments. Transmission / reception method.