JP2000174679A - Diversity receiver and diversity control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten time required for the judgement of antenna changeover and to highly efficiently transmit data. SOLUTION: In this diversity control method, the correlation value between a spread code extracted from radio signals received by a selected first or second reception antenna 10-1 or 10-2 and the spread code set beforehand is obtained and a selection means 201 for alternately selecting one of the first and second reception antennas is controlled based on the correlation value. Also, preamble data for establishing the synchronization of packet communication data is detected from the radio signals and the correlation value is obtained from the preamble data area of the packet communication data. Also, in the case that the correlation value relating to the radio signals received by the selected one of the first and second reception antennas is less than a prescribed reference value set beforehand, the selection means is controlled and the other one of the first and second reception antennas is selected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diversity receiver suitable for use as a receiver for spread spectrum communication applied to mobile communication and the like, and to a diversity control method in such a receiver.

[0002]

2. Description of the Related Art A conventional diversity receiving apparatus compares received electric field strengths or correlation values received from a plurality of antennas and selects a signal having the best reception state. That is, in such a conventional method, the reception state of all the plurality of antennas is detected and compared, and the best signal is selected.

[0003]

For this reason, it is necessary for the transmitting side to transmit long preamble data necessary for detecting the reception state of all antennas, and to transmit effective data required for the upper layer in communication. Data transmission efficiency was reduced due to an increase in data other than the above. In particular, in high-speed packet communication, there is a problem that the communication throughput decreases due to an increase in preamble data for diversity control.

The present invention has been made in view of such a background, and provides a diversity receiver and a diversity control method capable of transmitting data with high efficiency with a short time required for antenna switching determination. It is an object.

[0005]

In order to solve the above-mentioned problems, according to the present invention, the first and second receiving antennas and the first and second receiving antennas are provided. Selecting means for selecting one of the following, a spreading code extracted from a radio signal received by the selected first or second receiving antenna, and a spreading code stored in a storage means in advance. And a control means for controlling the selection means based on the correlation value. Also, in the invention according to claim 2, in the diversity receiver according to claim 1, the correlation detecting means detects preamble data for establishing synchronization of packet communication data from the radio signal. A preamble detecting means is provided, wherein the correlation value is obtained from a preamble data area of the packet communication data. According to a third aspect of the present invention, in the diversity receiver according to any one of the first and second aspects, the control means may control one of the selected first or second receiving antennas. When the correlation value related to the radio signal received by the above is less than a predetermined reference value set in advance, the selecting means is controlled to select the other of the first and second receiving antennas. According to a fourth aspect of the present invention, in the diversity receiver according to any one of the first and second aspects, the control unit controls the radio signal received by the selected first receiving antenna. If the correlation value is less than a predetermined reference value set in advance,
The present invention is characterized in that the selection means is controlled to select the second receiving antenna. Further, in the invention according to claim 5, a correlation value between a spreading code extracted from a radio signal received by the selected first or second receiving antenna and a predetermined spreading code is obtained. And selecting means for selecting one of the first and second receiving antennas based on the correlation value. Also, in the invention according to claim 6, in the diversity control method according to claim 5, preamble data for establishing synchronization of packet communication data is detected from the radio signal, and the packet communication data The correlation value is obtained from a preamble data area. According to a seventh aspect of the present invention, in the diversity control method according to the fifth or sixth aspect, the radio signal received by one of the selected first and second receiving antennas is provided. When the correlation value is less than a predetermined reference value, the selector is controlled to select the other of the first and second receiving antennas. Also, in the invention according to claim 8, in the diversity control method according to any one of claims 5 and 6, the selected first
When the correlation value related to the radio signal received by the receiving antenna is less than a predetermined reference value, the selecting unit is controlled to select the second receiving antenna.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a diversity receiver according to one embodiment of the present invention.
_10-1 and _10-2 shown in FIG. 1 are antennas for receiving spread spectrum signals, and 201 is a switch. This switch 201 is controlled by diversity control described later, and is used to control the antenna _10-1 or 10-1.
_-2 is alternatively selected.

Reference numeral 202 denotes a correlation detection unit,
The correlation value between the spread code detected from the received signal _SRCV selectively output by 1 and the spread code written in the spread code memory 205 for use in despreading by the receiving circuit 203 described later is detected.

FIG. 2 is a block diagram showing a detailed configuration example in the correlation detecting section 202. Thus, the correlation detection unit 20
_Reference numeral 2 denotes a preamble detector 202a for detecting preamble data to be described later from the received signal S _RCV , a spreading code (to be described later) detected from the received signal S _RCV, and a control unit 204.
The correlation value with the spreading code given from is calculated.

Reference numeral 203 denotes a receiving circuit, which receives the above-mentioned received signal.
(Despreading) the received data D _RCVIs output.
Reference numeral 204 denotes a control unit, which outputs a signal from the correlation detection unit 202 described above.
Reads the relevant value and sends the antenna control data to the switch 201.
D_ANTTo send antenna 10_-1And 10_-2Any of
Diversity control is performed to select whether or not.

In wireless data transmission by packet communication,
Generally, preamble data is added to the head of a packet of wireless data. Based on this data, the receiver establishes synchronization with the received data, and detects the head of the valid data portion in the wireless data packet.

[0011] In this embodiment, by utilizing this preamble data, among the antenna 10 _-1 and the antenna _10-2, one compares determine is receiving better signals. That is, each antenna _{10 -1} in the preamble data received, comparing the correlation value of the radio data received by the antenna _10-2, selects an antenna _{10 -1} or _{10 -2} larger correlation values by the switch 201.

By the way, in spread spectrum communication, the transmitting side spreads a carrier wave based on a predetermined code when transmitting the carrier wave. This predetermined code is called a spreading code. In such spread spectrum communication, the same spreading code is used on the transmitting side and the receiving side.

In the present embodiment, a spreading code unique to the received carrier is detected from the received carrier, and a correlation value with a predetermined spreading code is obtained. At this time, it is determined that the larger the correlation value is, the better the reception state is, and the smaller the correlation value is, the worse the reception state is.

FIG. 3 is a flowchart showing an example of the flow of processing in this embodiment. In this embodiment, first select the antenna _10-1 by the antenna control data _{D ANT,} it receives the preamble data from the antenna _{10 -1} in this state (step St1).
Here, the correlation value on the antenna _10-1 side is obtained by the correlation detection unit 202, and the correlation value is read by the control unit 204 (Step St2).

The control unit 204 checks whether the read correlation value is greater than a predetermined reference value provided in advance (step St3), is smaller than the reference value the switch 201 by the antenna control data D _ANT Switch to the antenna _10-2 side (Step St4). Thereafter, the data following the preamble data is received by the receiving circuit 203 (Step St5).

As described above, in this embodiment, antenna switching is performed only once at the maximum. Therefore, preamble data required for diversity control can be shortened, and data transmission efficiency can be improved.

[0017]

As described above, according to the present invention, the correlation between the spreading code extracted from the radio signal received by the selected first or second receiving antenna and the preset spreading code is obtained. A value is obtained, and a selection unit that selects one of the first and second receiving antennas is controlled based on the correlation value. Also, preamble data for establishing synchronization of packet communication data is detected from the radio signal, and a correlation value is obtained from a preamble data area of the packet communication data. When the correlation value related to the radio signal received by one of the selected first and second receiving antennas is less than a predetermined reference value, the selection unit is controlled to control the first or second reception antenna. Select the other side of the antenna. Further, when the correlation value related to the radio signal received by the selected first receiving antenna is less than a predetermined reference value, the selecting unit is controlled to select the second receiving antenna. This makes it possible to achieve a diversity receiver and a diversity control method capable of transmitting data with high efficiency and a short time required for the determination.

That is, in the present invention, since the number of times of antenna switching is minimized, the preamble data required for diversity control transmitted from the transmitting side is minimized,
It is possible to improve the transmission efficiency of wireless data.

Since the criterion for antenna switching is the level of the correlation value, there is no influence of temperature drift of the automatic gain control circuit. That is, diversity control with higher accuracy is realized by comparing the accuracy of the data reception state, rather than simply comparing the reception electric field strength levels, and performing the diversity control.

Since only a single antenna is switched in the high frequency stage using a single correlator and a receiving circuit,
A great effect can be obtained by an extremely simple circuit configuration.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a diversity receiver according to one embodiment of the present invention.

FIG. 2 is a block diagram illustrating a detailed configuration example in a correlation detection unit 202.

FIG. 3 is a flowchart illustrating an example of a processing flow according to the first embodiment.

[Explanation of symbols]

_10-1 antenna (first antenna) _10-2 antenna (second antenna) 201 switch (selection unit) 202 correlation detection unit (correlation detection unit) 202a preamble detector (preamble detection unit) 202b correlator 203 reception circuit 204 control unit (control means) 205 spreading code memory (storage means) D _ANT antenna control data D _RCV reception data S _RCV reception signal

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K022 EE02 EE13 EE31 EE36 5K059 CC03 DD02 DD05 DD12 DD27 EE02

Claims (8)

[Claims] A first receiving antenna and a second receiving antenna.
_-1 , 10 _-2 ) and one of the first and second receiving antennas (201).
And a correlation detecting means (202) for obtaining a correlation value between a spreading code extracted from a radio signal received by the selected first or second receiving antenna and a spreading code previously stored in the storage means (205). And a control means (204) for controlling the selection means based on the correlation value. 2. The communication apparatus according to claim 1, wherein the correlation detection unit includes a preamble detection unit configured to detect preamble data for establishing synchronization of packet communication data from the wireless signal. The diversity receiver according to claim 1, wherein a correlation value is obtained. 3. The control unit, when the correlation value related to the radio signal received by the selected one of the first and second receiving antennas is less than a predetermined reference value set in advance, 3. The diversity receiver according to claim 1, wherein the diversity receiver is controlled to select the other of the first and second receiving antennas. 4. The control means controls the selection means when the correlation value relating to the radio signal received by the selected first receiving antenna is less than a predetermined reference value set in advance. 3. The diversity receiver according to claim 1, wherein two reception antennas are selected. 5. A correlation value between a spreading code extracted from a radio signal received by the selected first or second receiving antenna and a predetermined spreading code, and based on the correlation value, A diversity control method, characterized by controlling a selection means for selecting one of the first and second receiving antennas. 6. The apparatus according to claim 5, wherein preamble data for establishing synchronization of packet communication data is detected from the radio signal, and the correlation value is obtained from a preamble data area of the packet communication data. Diversity control method. 7. When the correlation value relating to a radio signal received by one of the selected first and second receiving antennas is less than a predetermined reference value set in advance, controlling the selecting means to control the 7. The diversity control method according to claim 5, wherein the other of the first and second receiving antennas is selected. 8. When the correlation value relating to the radio signal received by the selected first receiving antenna is less than a predetermined reference value set in advance, the selecting unit is controlled to control the second receiving antenna. The diversity control method according to claim 5, wherein the method is selected.