Method and device for estimating frequency ramp and frequency deviation in satellite mobile communication system

A satellite mobile communication and frequency offset estimation technology, applied in the field of communication, can solve the problems of low accuracy and high computational complexity

CN102437992AInactive Publication Date: 2012-05-02PEKING UNIV
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2012-05-02
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a method and a device for estimating a frequency ramp and a frequency deviation in a satellite mobile communication system. The method comprises the following steps of: according to parameters of an actual communication system, obtaining a range of a normalized frequency ramp value aD and calculating a trial interval delta aD of the frequency ramp value; carrying out repeated test on the normalized frequency ramp value aD by utilizing a frequency deviation estimating method, wherein the test interval each time is delta aD, one or a plurality of (aD, fD) number pairs are obtained in each trial process, and a set is formed by all the (aD, fD) number pairs after all the test processes are completed; and substituting all the (aD, fD) number pairs in the set into a likelihood function G (aD, fD), searching the (aD, fD) number pair capable of ensuring the likelihood function to attain the maximum value and using the (aD, fD) number pair as estimation values of the frequency ramp and the frequency deviation. The method and the device have the advantages of low SNR (Signal to Noise Ratio) threshold, low computational complexity and high estimation accuracy. In the actual application, the existing module can be continuously used in the method for estimating the frequency deviation, the estimation on the frequency ramp can be realized without great improvement, and the method and the device are very convenient.
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Description

technical field

[0001] The invention relates to the field of communication technology, in particular to a method and device for estimating frequency ramp-up and frequency offset in a satellite mobile communication system. Background technique

[0002] In the satellite mobile communication system, the carrier synchronization problem between the transceiver and the receiver greatly affects the performance of the system. Due to the relative motion between the satellite or the base station and the receiver, there are Doppler frequency ramp-up (referred to as frequency ramp-up in this article), Doppler frequency offset (referred to as frequency offset in this article), and the like. Whether the frequency ramp and frequency offset can be estimated and compensated quickly and correctly is the premise of receiving data correctly, and it is also an indispensable link in the satellite mobile communication system. Pilot symbol-assisted modulation technology can improve the performance...

Examples

Embodiment Construction

[0039] The method of the present invention is referred to as "frequency ramp-up heuristic method", and the specific implementation is as follows (flow process see figure 1 ):

[0040] Step 1, by calculation or measurement, obtain the frequency ramp value a of the actual communication system (for example, in low-orbit satellite communication, when the carrier frequency is 7GHz, the typical maximum frequency ramp value is about 500Hz / s), divided by the carrier symbol rate f s The square of the normalized frequency ramp-up value a D upper limit of

[0041] | a D | max = a f s 2

[0042] The method of the present invention needs to a D Equally spaced trials are performed, given that the key factor affecting carrier synchronization performance is the normalized total...