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Detection method for multiuser and receiver for multiuser

A multi-user detection and receiver technology, applied in multiplexing communication, code division multiplexing system, communication between multiple stations, etc., can solve problems such as non-repetition

Inactive Publication Date: 2004-06-09
INT BUSINESS MASCH CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0027] However, commercial CDMA standards such as IS-95 use very long-period PN spreading codes which, for reasonable observation times, are considered to be completely random rather than repetitive

Method used

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  • Detection method for multiuser and receiver for multiuser
  • Detection method for multiuser and receiver for multiuser
  • Detection method for multiuser and receiver for multiuser

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Embodiment Construction

[0056] figure 1 A schematic illustration of a wireless communication system 20, in particular a cellular system, according to a preferred embodiment of the present invention is shown. Base station 22 sends downlink signals to a plurality of users 24 and receives uplink signals from the users in reply. The signal is modulated by DS-CDMA mode using PSK modulation, as described in the technical background of the present invention. To separate and process signals received from multiple users 24, base station 22 utilizes a novel detection scheme using constrained statistical patterns, as detailed below.

[0057] figure 2 A block diagram schematically illustrating elements of a transmitter 26 operated by a user 24 in the system 20 is shown. The operation of the transmitter is mathematically represented by equations (2) and (3) above. Each symbol b(t) to be transmitted is multiplied by a complex PN spread spectrum waveform with distinct real parts (I)C I (t) and imaginary part ...

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Abstract

A method for multi-user detection includes receiving a complex input signal due to a superposition of waveforms encoding symbols in a constellation of fixed magnitude and variable phase, which symbols are transmitted respectively by a plurality of transmitters in a common frequency band. The complex input signal is sampled at sampling intervals over the duration of an observation period to provide a sequence of complex samples. The sequence of complex samples is processed to determine soft decision values corresponding to the symbols transmitted by the plurality of the transmitters in the observation period, while constraining the soft decision values to a circle in a complex plane. The soft decision values are projected onto the constellation to estimate the transmitted symbols.

Description

technical field [0001] The present invention relates generally to data signal processing, and more particularly to methods and systems for simultaneously receiving and processing signals from multiple transmitters sharing a common frequency by using Code Division Multiple Access (CDMA). Background technique [0002] CDMA has been used extensively in cellular and other wireless systems that multiplex communications between multiple users in a common frequency band. In direct sequence (DS) CDMA, the transmitter multiplies each user's signal by an eigencoded waveform. The encoded waveforms of the different users are in the form of "pseudo-noise" (PN) sequences, also called spreading codes, and are chosen so as to be as mutually orthogonal as possible. The receiver receives a composite signal consisting of the sum of all user signals, which overlap in time and frequency. To recover a single signal for a given user, the receiver correlates the synthesized signal with the user's...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/69H04B1/707H04L25/06
CPCH04B1/7105H04L25/067
Inventor 谢伊·本-戴维埃赫德·卡宁雅各布·欣瓦尔德
Owner INT BUSINESS MASCH CORP