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CDMA transmitting device and CDMA transmitting method

一种发送装置、码分复用的技术，应用在码分多路复用系统、多路复用通信、正交多路复用系统等方向，能够解决传输效率降低、传输延迟增加、差错率特性恶化等问题

Inactive Publication Date: 2005-07-27
PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the transmission delay increases as the number of retransmissions increases, there is a major problem that transmission efficiency decreases
Here, there is also a method of stopping retransmission when a certain delay time is reached, but this creates a new problem of deterioration of the error rate characteristic

Method used

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  • CDMA transmitting device and CDMA transmitting method
  • CDMA transmitting device and CDMA transmitting method
  • CDMA transmitting device and CDMA transmitting method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] figure 2 A schematic configuration of the wireless transmission device 100 according to Embodiment 1 of the present invention is shown. The CDMA transmission device 100 inputs the modulated transmission signal to the control unit 102 of the code division multiplexing unit 101. The control unit 102 outputs the input transmission signal to a plurality of spreading units 103 to 106 that perform spreading processing using different spreading codes. Here, the spreading sections 103 to 106 use mutually perpendicular spreading codes (that is, spreading codes whose correlation is "0") to perform spreading processing.

[0020] The spread signal obtained by the spreading section 103 is sent to the selection section 109. The spread signals obtained by the spreading sections 104, 105, and 106 are sent to the selection section 107. The selection unit 107 selectively outputs the spread signal based on the signal indicating the number of retransmissions from the control unit 102. Specif...

Embodiment 2

[0040] In this embodiment, it is proposed that the communication method (generally referred to as the OFDM-CDMA communication method) that combines the CDMA communication method and the OFDM (Orthogonal Frequency Division Multiplexing) communication method will increase as the number of retransmissions increases. The spreading code assigned to the retransmission signal.

[0041] Here, because the OFDM-CDMA communication method can remove the interference of the symbols before and after in the multipath environment with the guard interval, if the transmission method of the present invention can be applied, that is, as the number of retransmissions increases, the signal allocated to the retransmission is increased. The number of spreading codes can further improve the error rate characteristics in a multipath environment and increase the suppression effect of the number of retransmissions.

[0042] in Figure 4 Middle, for and figure 2 The corresponding parts are attached with the ...

Embodiment 3

[0046] In this embodiment, it is proposed to change the number of spreading codes allocated to the retransmission signal according to the number of multiplexing of all codes of the transmission signal. In other words, considering the fact that the code multiplexing number of the signal sent after the final code division multiplexing is not only the signal sent to one user, but also the signal sent to other users, according to all the code multiplexing numbers To change the number of spreading codes allocated to the retransmission signal. As a result, compared with Embodiment 1, the error rate characteristics of the retransmission signal can be further improved, and the number of retransmissions can be further reduced.

[0047] in Figure 5 Middle, for and figure 2 The corresponding parts are attached with the same reference numerals. The CDMA transmitting apparatus 400 of this embodiment has the same number of code division multiplexing units 401-1 to 401-n as the number of users...

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Abstract

A transmit signal is spread by a plurality of spreading sections 103, 104, 105, and 106, using different spreading codes. A selection section 107 increases the number of spread signals to be output as the number of retransmissions increases. By this means, a retransmission signal spread by means of many spreading codes is code division multiplexed. As a result, retransmission signal error rate characteristics are improved on the receiving side by despreading this code division multiplexed signal using the same plurality of spreading codes as on the transmitting side, and selecting or combining the despreading results with the greatest correlation power thereamong. Also, since the degree of code multiplexing is increased proportionally as the number of retransmissions increases, retransmission signal error rate characteristics can be improved without lowering spectral efficiency unnecessarily.

Description

Technical field [0001] The present invention relates to a wireless transmission device using a CDMA (Code Division Multiple Access) method, a wireless transmission device using an OFDM-CDMA method, and a method thereof. Background technique [0002] In the past, in wireless communication using the CDMA method, a signal is transmitted after spreading, and the received signal is despread using the same spreading code at the receiving end as at the transmitting end. Therefore, in the wireless communication of the CDMA method, by preparing a plurality of mutually perpendicular spreading codes, it is possible to code-division multiplex signals sent to a plurality of users and then transmit them on the same frequency band. [0003] In addition, in CDMA communication, when the receiving end detects a transmission error, it requests the transmitting end to send the same signal again, thereby improving the error rate characteristics of the received data. [0004] figure 1 Shows the stru...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L1/00H04B1/69H04B7/26H04J11/00H04J13/00H04W52/04H04W72/04H04W76/00H04W76/02
CPCH04B1/69H04L5/0021H04L1/1867H04L1/0003H04B1/692
Inventor 须藤浩章
Owner PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA
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