Joint carrier frequency offset and channel estimation for OFDM systems with two receive antennas

Abstract

Carrier frequency offset (CFO) in OFDM systems results in loss of channel orthogonality and hence degrades the system's performance. In this paper, we propose a new method for joint CFO/channel estimation for OFDM systems with two receive antennas. Our method avoids the complexity of full search methods in one or two dimensions. Using one training OFDM symbol and utilizing the knowledge of the structure of the inter-channel interference that results from CFO, we develop a two-stage estimation procedure. The first stage derives an initial CFO/channel estimate based on a one shot minimization step. The second stage refines this joint estimate by conducting a small CFO search in the vicinity of the initial estimate. This procedure provides CFO estimates over a full range of ÀN/2-N/2, (N: number of subcarriers), as well as the channel estimates. Computer simulations show an excellent performance that is very close to the Cramer-Rao lower bound and superior to some existing methods. The effect of antenna correlation on performance is also investigated through computer simulations, showing small performance degradation even at medium correlation coefficients (0.3-0.6).

BER analysis and interference mitigation for GO‐OFDMA transmission

“…Last part is added modified noise. By assigning these tags to different portions of received data bits, (A4) can be transformed into (8).…”

“…Effect of CFO in different schemes had been investigated in previous literature. [2][3][4][5][6][7][8] One way is to use multiuser detection (MUD). But MUD is relatively complex that imposes computational as well as power burden on the receiver and its complexity increases with the number of users.…”

Analysis and design of joint CFO/channel estimate techniques for a cooperative STBC‐OFDM system

“…In Huang et al, 16 the CFO synchronization involving the subspace decomposition is achieved by multidimensional searching of correlation peaks for an OFDM training block with a tile structure in the frequency domain (FD). A closed form solution 17 for a two-stage CFO/channel estimation scheme is derived for the OFDM system with two receive antennas. Using superimposed training sequence, a hybrid algorithm is proposed to estimate the fast fading channel in presence of Doppler offset for MIMO relay systems with high mobility.…”