TAILIEUCHUNG - MIMO Systems Theory and Applications Part 9

Tham khảo tài liệu 'mimo systems theory and applications part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 270 MIMO Systems Theory and Applications The above equation implies that local minimum solution does not exist and the optimum solution with minimum square error is definitely determined as well as in Eq. 8 . Thus by differentiating this equation respect to wt2 we can obtain Vwt2E l e2 2 -4E hh h wt2E s2 2 4E hhhJ wt2 wH2E hhh wt2 2E hh h wnw E hh h wt 2E S1 2 14 After substituting this equation for Eq. 10 and removing the expectation operation Eq. 10 is reduced to wf2 m 1 w2 m 2 HH12 m e2 m --1 HHw w d lw 2 m I s 112 j 15 where r2 m H wt1 m s1 wt2 m s2 . The optimum weight matrix Wt is obtained by updating weight vectors of these two recursive equations . Eqs. 11 and 15 . The above discussion on 2x2 MIMO system is easily extended to Ntx2 or 2xNr MIMO system . for Ntx2 MIMO system the received signal at the virtual receiver can be given as PỌ1 1 1 x .2 J wt11 w 12 WtNt 1 W ỈNt 2 hh h wt11 .L wt12 J. s1 _s2. X A HHH w 1 wt2 s1 1 s2 J 16 t WtN 1 WtN 2 where wt1 wt11 wtNt1 T and wt2 wt12 wtNt2 T. From this equation it is clear that optimum weight matrixes for Ntx2 MIMO system are obtained by the same way as 2x2 MIMO case since channel autocorrelation matrix HHH is given as NtxNt matrix. For case of 2xNt MIMO system since the autocorrelation matrix HHH is given as 2x2 matrix the same discussion as 2x2 MIMO case can be applied. In addition the proposed method can be applied to case where the rank of channel matrix is more than two . when the rank of channel matrix is 3 optimum weight matrix is obtained by minimizing the error function defined so that the third weight vector wt3 is orthogonal to both the first and second weight vectors of wt1 and wt2 where the weight vectors obtained in the previous calculation . wt1 and wt2 are used as the fixed vectors in this case. Thus it is obvious that this discussion can be extended to case of channel matrix with the rank of more than 3. In the proposed method the parameter convergence speed depends on initial values .

TỪ KHÓA LIÊN QUAN
Đã phát hiện trình chặn quảng cáo AdBlock
Trang web này phụ thuộc vào doanh thu từ số lần hiển thị quảng cáo để tồn tại. Vui lòng tắt trình chặn quảng cáo của bạn hoặc tạm dừng tính năng chặn quảng cáo cho trang web này.