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Carrier frequency bias estimation with OFDMA up link system intersection

A carrier frequency offset and link system technology, applied in multi-frequency code systems, signal channels, etc., can solve problems such as low frequency diversity, carrier frequency offset, and reduced number of access users

Inactive Publication Date: 2006-08-16
TSINGHUA UNIV
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

The frequency diversity of the block allocation method is not high, which may cause the subcarrier of a certain user to be completely in deep fading; and the subcarrier guard interval is required between users, which will reduce the number of access users
The interleaved allocation method can provide the maximum frequency diversity and channel diversity, but because the subcarriers of different users are close to each other, this method is easy to introduce inter-user interference
[0007] At present, there is no feasible method to solve the estimation problem of carrier frequency offset in the interleaved OFDMA uplink system, but by constructing the signal structure of the receiver, drawing on the existing DOA estimation method, such as multiple signal classification method (MUSIC), using an OFDMA symbol The block can realize the joint estimation of the frequency offset of multiple users

Method used

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  • Carrier frequency bias estimation with OFDMA up link system intersection
  • Carrier frequency bias estimation with OFDMA up link system intersection
  • Carrier frequency bias estimation with OFDMA up link system intersection

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Embodiment Construction

[0079] The specific implementation of the present invention will be described in detail below with reference to the accompanying drawings.

[0080] figure 2 It is a block diagram of the transmitter structure of the interleaved OFDMA uplink, assuming that the number of subcarriers in the system is N, the number of users is M, and the number of subchannels is Q (satisfying M≤Q), and the number of subcarriers allocated to each user If they are the same, each subchannel has P=N / Q subcarriers. The subcarrier numbers of the subchannel {q} are {q, Q+q, ..., (P-1)Q+q}, q=0, 1, ..., Q-1. Suppose the subchannel occupied by the mth user is q (m) ,{S 0 (m) , S 1 (m) ,...,S P-1 (m)} are the P modulation symbols of the user in one OFDMA symbol block.

[0081] At the transmitting end of the mth user, the {S p (m)} p＝0 P-1 Mapped to N subcarriers, get {X i (m)} i＝0 N-1 , i=0, 1, . . . , N-1 represents the frequency sampling sequence number. Its corresponding relationship is...

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Abstract

The invention modifies the signal structure of receiver to make the received signal taking the numbers of sub-carrier in each sub-channel as its periodic time in order to rearrange the signal by the receiver. After calculating covariance matrix, Jacobi eigenvalue and eigenvector, Akaike Information Criterion (AIC) is used to estimate the numbers of subscribers. After frequency deviation spectrum is figured out, through rough estimation and precision estimation, the estimated value of subscriber frequency deviation is obtained.

Description

technical field [0001] The invention belongs to the field of broadband wireless access technology, in particular to a carrier frequency offset estimation of an Orthogonal Frequency Division Multiplexing Access (OFDMA) uplink system using an interleaved (Interleaved) subcarrier allocation method method. Background technique [0002] In recent years, OFDM or OFDMA technology has been adopted in broadband wireless communication systems. OFDM / OFDMA has become one of the most competitive transmission technologies in the next generation of mobile communications due to its strong ability to resist multipath fading and high spectrum utilization. [0003] OFDMA refers to a new multiple access method obtained by allocating different subcarriers for each user in a multi-user OFDM system. In the OFDMA system, users occupy different subcarriers, so multiple users can transmit data at the same time; and because the subcarriers overlap each other, there is no need to add a guard band for...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26H04L5/02
Inventor 范达曹志刚樊平毅
Owner TSINGHUA UNIV
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