 it is reasonable to use MRC for decoding, yielding (1.28) |Hml2 + IHH-m12 where Hm is the CFR at subcarrier m, and is the received signal in the FD corresponding to the i-th transmitted OFDM symbol (i E {1,2}). From the above, it can be found that compared with the one-path cancellation approach, the two-path cancellation approach is conveniently compatible with the traditional OFDM transceiver design without any modifications. 1.4.2.1 MCVT Scheme For the MCVT scheme, conversion operation is adopted. The two consecutive transmitted OFDM symbols are of the form X(1) = [X,X, ,Xn-1] = -X1]. From Eq. (1.28), the decision variable at the m-th subcarrier (m = 0,...,N - 1) is given by k=0,k#m (1.29) where the CFO of the first symbol is E, the CFO of the second symbol is E + , and = 1,2) is the noise at the m-th subcarrier of the p-th path. According to Eq. (1.29), the CIR of the MCVT scheme can be expressed as (1.30) k=0,k#m For the flat fading channel, the CIR of the MCVT scheme becomes A&)|2 (1.31) 1.4.2.2 MCJT Scheme For the MCJT scheme, conjugate operation is adopted. In this case, the two con- secutive transmitted OFDM symbols are given by X(1) = [X,XX, ,XN-1] and X(2) = to Eq. (1.28), the decision variable at the m-th (m E {0,1,..., N - 1}) subcarrier is given by 1 ICI Cancellation Techniques Based on Data Repetition for OFDM Systems k=0,k#m (1.32) According to Eq. (1.32), the CIR of the MCVT scheme can be expressed as (1.33) k=0,k#m For the flat fading channel, the CIR of the MCJT scheme is given by (1.34) Similarly to MCSR, we see here that the denominator in the CIR expression is the sum- mation over Sk(E) +Stk(E + -A&), which is approximately zero for k # 0 and small AE. In addition, by comparing with Eq. (1.26), it can be found CIRMCIT 22 CIRMCSR when AE = 0. Finally, it is worth noting that in flat fading channels, the CFRs at all subcarriers are same, and the CFR coefficients are inherently canceled in the CIR expression. Thus, the CIR of each scheme, namely Eqs. (1.20), (1.23), (1.26), (1.31), and (1.34),