Pilot sequence structure in MIMO-OFDM/OQAM (Multi-input Multi-output-Orthogonal Frequency Division Multiplexing/Offset Quadrature Amplitude Modulation) system and channel estimation method

A pilot sequence and channel estimation technology, which is applied in the field of channel estimation, can solve the problem of multipath fading channel destroying the orthogonality characteristics, and achieve the effects of reducing correlation, eliminating channel multipath interference, and reducing linearity requirements

CN103281265AInactive Publication Date: 2013-09-04UNIV OF ELECTRONICS SCI & TECH OF CHINA
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2013-09-04
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a pilot sequence structure in an MIMO-OFDM / OQAM (Multi-input Multi-output-Orthogonal Frequency Division Multiplexing / Offset Quadrature Amplitude Modulation) system and a channel estimation method. Different pilot sequences are adopted by different antennae, the pilot sequence of each antenna is composed of three segments of symbol sequences, the length of each symbol sequence accords with the number of subcarriers, wherein the first segment of symbol sequence and the third segment of symbol sequence are all-zero symbol sequences, pilot signals are arranged at equal intervals in the second segment of symbol sequence, the pilot signal positions of all the antennas are different, the symbols of the pilot signals are randomly chosen from a candidate symbol set, and the interval between the pilot signals is two times the number of the antennas. The channel estimation method put forward by the invention can be utilized to eliminate inter-symbol interference and inter-subcarrier interference caused by multipath interference, so that the accuracy of the channel estimation of the MIMO-OFDM / OQAM system can be increased. Meanwhile, the pilot sequence structure decreases the peak-to-average power ratio of transmitted signals, and can meet the linear dynamic range of a radio frequency front-end high power amplifier and decrease the linearity requirement of the MIMO-OFDM / OQAM system on the high power amplifier.
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Description

technical field

[0001] The invention belongs to the technical field of channel estimation in MIMO-OFDM / OQAM systems, and more specifically relates to a pilot sequence structure and channel estimation method in MIMO-OFDM / OQAM systems. Background technique

[0002] Among existing communication technologies, OFDM / OQAM (Orthogonal Frequency Division Multiplexing / offset Quadrature Amplitude Modulation, Orthogonal Frequency Division Multiple Access technology based on Interleaved Quadrature Amplitude Modulation) system is known for its high spectrum utilization, good The time-frequency focusing feature has become one of the main candidate technologies for future mobile multimedia communications. For a detailed introduction, see (Le Floch, M. Alard, and C. Berrou, "Coded Orthogonal Frequency Division Multiplex," Proceedings of the IEEE, vol.83, pp.982–996, June 1995.).

[0003] The mathematical expression of the transmitted signal s(t) of the OFDM / OQAM system is:

[0004] ...

Examples

Embodiment

[0055] Figure 4 It is a schematic diagram of an embodiment of the pilot sequence structure in the MIMO-OFDM / OQAM system of the present invention. Such as Figure 4 As shown, the number of transmit antennas in this embodiment is N=2. In general, the set of candidate symbols Q can be {1,-1} or a set of complex signals with constant modulus. In this embodiment, the set of candidate symbols Q={1,-1}. In the pilot sequence corresponding to transmitting antenna 1, the first symbol sequence 7 and the third symbol sequence 9 are all zeros, and in the second symbol sequence 8, the first symbol a 1,1 =1, the fifth symbol a 1,2 =-1, the 9th symbol a 1,3 =-1, and so on, and the remaining symbols are zero. The 1st, 5th, 9th... symbols in the second symbol sequence 8 are used as pilot signals for channel estimation of the transmitting antenna 1 by the receiving end. In the pilot sequence corresponding to the transmitting antenna 2, the first symbol sequence 10 and the third symbol se...