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Signal quality estimation for continuous phase modulation

A phase modulation and signal quality technology, applied in the field of communication, can solve problems such as system performance degradation and inaccurate C/I estimation

Inactive Publication Date: 2010-10-13
QUALCOMM INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Approximating the CPM signal to a PSK modulated signal, while simplifying receiver design, leads to inaccurate C / I estimates for some operating conditions
Inaccurate C / I estimates can degrade system performance

Method used

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  • Signal quality estimation for continuous phase modulation
  • Signal quality estimation for continuous phase modulation
  • Signal quality estimation for continuous phase modulation

Examples

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Embodiment Construction

[0018] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments or designs.

[0019] The C / I estimation techniques described herein can be used for various types of CPM signals and for various wireless communication systems. For clarity, these techniques are described specifically for the GMSK modulated signals used in GSM.

[0020] figure 1 A block diagram of a transmitting entity 110 and a receiving entity 150 in a GSM system is shown. The transmitting entity 110 may be a base station or a wireless device, and the receiving entity 150 may also be a wireless device or a base station. At transmitting entity 110 , a transmit (TX) data processor 112 receives, formats, codes, and interleaves data based on one or more coding and interleaving schemes, and provides an input bitstream to a GMSK modula...

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Abstract

A received continuous phase modulation (CPM) signal (which is formed with a set of pulse shaping functions) is approximated as a phase shift keying (PSK) modulated signal (which is formed with just the dominant pulse shaping function having the largest energy). Channel estimation and data detection are performed in accordance with the CPM-to-PSK approximation. A signal power estimate and a noise power estimate are obtained for the received CPM signal and have errors due to the CPM-to-PSK approximation. The difference Delta between the energy of the dominant pulse shaping function and the energy of the remaining pulse shaping functions is determined. An approximation error is estimated based on the signal power estimate and the difference Delta. A C / I estimate for the received CPM signal is computed based on the signal power estimate, the noise power estimate, and the approximation error estimate.

Description

technical field [0001] The present invention relates generally to communication, and more particularly to signal quality estimation in wireless communication systems. Background technique [0002] In a wireless communication system, the transmitter first digitally processes the traffic / packet data to obtain encoded data. The transmitter then modulates the carrier signal with the encoded data to obtain a modulated signal more suitable for transmission over the wireless channel. Modulation may be performed based on various modulation schemes. One modulation scheme widely used throughout the world is continuous phase modulation (CPM). With CPM, the phase of the carrier signal is modulated by the encoded data in a continuous rather than discontinuous manner. Therefore, CPM has several desirable characteristics, such as (1) a constant envelope of the modulated signal, which allows the use of an efficient power amplifier to transmit the signal, and (2) a compact spectrum of the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/18
CPCH04L1/20H04L27/22
Inventor 赖桂江阿鲁娜瓦·乔杜里
Owner QUALCOMM INC