Method and apparatus for multipath delay estimation in direct sequence spread spectrum communication systems

A technique for channel coefficient and estimation, applied in transmission systems, communications between multiple stations, electrical components, etc.

Inactive Publication Date: 2001-03-21
TELEFON AB LM ERICSSON (PUBL)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0014] The invention solves the problem of multipath delay estimation when a direct sequence spread spectrum (DS-SS) signal is transmitted in a multipath fading channel

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  • Method and apparatus for multipath delay estimation in direct sequence spread spectrum communication systems
  • Method and apparatus for multipath delay estimation in direct sequence spread spectrum communication systems
  • Method and apparatus for multipath delay estimation in direct sequence spread spectrum communication systems

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Embodiment Construction

[0029] The present invention will now be described in connection with a pilot channel-based system such as IS-95 downlink. The pilot channel for such a system is unmodulated. However, the present invention can also be applied to other systems, such as systems using modulated pilot channels, pilot symbols, or no pilot signals at all. The invention is also described in the text of delayed tracking. It can be seen that the present invention can also be applied to initial delay estimation, in which there is no previously estimated delay to be updated.

[0030] A DS-SS communication system adopting the present invention is shown in image 3 in. The DS-SS transmitter 303 transmits the DS-SS signal through the radio channel 304, which is received by the receiver composed of the RF part 301 and the baseband processor 402. The RF part amplifies, filters, and down-mixes this signal to baseband frequency, typically OH E This signal is also typically sampled and quantized to generate data sam...

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Abstract

Multipath delay estimation of a direct sequence spread spectrum (DS-SS) signal transmitted in a multipath fading channel is accomplished by measuring the envelope of the signal to determine a new delay estimate. Delay estimates are also obtained in ray strength order, by subtracting out the influence of the stronger rays on the weaker ones. This subtraction approach can be performed iteratively, allowing further refinement of the delay estimates. Delay estimates can also be determined by minimizing the mean square error (MSE) between a measured correlation function and a modeled correlation function. The minimum mean square error (MMSE) approach can performed iteratively, to further refine the delay estimates. Maximum likelihood (ML) delay estimates can also be obtained by exploiting side information regarding the transmit and receive pulse shapes.

Description

Invention field [0001] The present invention relates to a method and equipment for estimating the transmission delay of a multipath radio signal, and more particularly to a method and equipment for estimating the delay of a multipath signal in a telecommunication system using direct sequence spread spectrum technology. equipment Background of the invention [0002] Because more of the radio spectrum is commercially available, and cellular phones have become commonplace, the field of radio communications is expanding at an extraordinary rate. In addition, there is currently an evolution from analog communication to digital communication. In digital communication, speech is expressed by a series of bits that are modulated and sent from the base station to the phone. The phone demodulates the received waveform to recover these bits, which are then converted back to speech. There is also a growing need for data services, such as e-mail and Internet access, which r...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/711H04B1/709H04B1/7113H04B7/26
CPCH04B1/7113H04B1/711H04B1/709
Inventor E·索洛尔G·波托姆利R·拉梅斯S·陈纳克舒
Owner TELEFON AB LM ERICSSON (PUBL)
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