Customer group pilot-frequency distribution method for orthogonal FDMA system
An orthogonal frequency division multiple access and pilot allocation technology, applied in the directions of orthogonal multiplexing system, multiplexing communication, electrical components, etc., can solve the failure of frequency domain interpolation algorithm and the destruction of subcarrier orthogonality , system performance degradation and other issues, to achieve the effect of improving the accuracy of channel estimation
Inactive Publication Date: 2005-12-21
BEIJING UNIV OF POSTS & TELECOMM
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Problems solved by technology
Because the spacing between adjacent subcarriers of such a user may exceed the coherence bandwidth, the frequency domain interpolation algorithm fails
In addition, due to the different Doppler shifts of the signals of different users, the orthogonality between subcarriers is destroyed, resulting in the degradation of system performance
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[0014] The user group pilot design method proposed by the invention is carried out in one time slot, and realizes the channel estimation of uplink multi-user access in the wireless system.
[0015] figure 1 It is a schematic diagram of the principle of user group composition adopted at the sending end in the present invention. Without loss of generality, the sender combines two users User 0 and User 1 to form a group, namely U G =2. Among the 2 users mentioned, the position subscript of the pilot and data subcarriers of the i-th user is S i ={μ i +v·d|v=0,...,V}, μ i , v, d ∈ Z, μ i ∈{0, 1, ..., d-1}, i=0, 1, that is, there are V pilot and data subcarriers of the i-th user, μ i is the starting position, and d is the position interval between two adjacent pilot or data subcarriers. Within the user group, the position P of the shared pilot subcarrier G0 = S 0 or S 1 , different users in the user group use orthogonal codes as pilot sequences, and the sequence length is ...
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The method includes steps: (1) at sending end, UG number of user constitutes a user group; each user in user group uses orthogonal code as pilot carrier sequence; length V of the said pilot carrier sequence is equal to number of pilot carrier of single user in user group. These users share position PG of pilot sub carrier; (2) UG pieces of pilot carrier are setup at different positions within a time slot; these positions of pilot carrier are corresponding to UG number of user; (3) the receiving end carries out channel estimation in frequency domain at UG positions of pilot carrier; (4) through interpolation in time domain, the receiving end obtains channel estimation in frequency domain of a time slot by using channel estimation in frequency domain at UG positions of pilot carrier.
Description
technical field [0001] The invention relates to a low overhead channel estimation algorithm when multiple users access the uplink of an Orthogonal Frequency Division Multiple Access wireless communication system. Background technique [0002] The principle of the OFDMA system is to distinguish multiple users through sub-carriers, which can provide dynamic user capacity and reduce interference between adjacent cells. It has been adopted by 802.16e and is very likely to be applied to future mobile communication (B3G) systems. [0003] For the uplink of the OFDMA system, one of the technical difficulties is to track the channels of different users synchronously. Different from the downlink, the signal received by the base station in the uplink is the superposition of signals from multiple users, and they each experience different fading channels, which is a very unfavorable factor. Therefore, the method in the downlink, that is, multiple users share the same pilot symbols, ca...
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IPC IPC(8): H04J11/00
Inventor 张建华张平何学奇周雯刘宝玲徐国鑫安载泳
Owner BEIJING UNIV OF POSTS & TELECOMM