Tham khảo tài liệu 'mobile and wireless communications-physical layer development and implementation 2012 part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | High-Rate Reliable Communications with Hybrid Space-Time Codes 131 The system equation for ZF-SQRD LQOSTBC over four symbol periods may be written as follows where subindices indicate antenna number and superindices indicate symbol period within a block r yi 4 . Ầ1 bl 2 - Kn - rs. 1 abba _SA J J y 1 - L nR y yR J hR 1 1 hnR2 K n J n 1 . . nR n 4 nR J 24 or equivalently Y HS N. 25 Matrix Y e C Rx4 represents the symbols received in a block. Matrix H is the channel matrix defined above. Matrix N e CnR x4 represents the noise added to each received symbol. Matrix S is composed of a spatial multiplexing block and nB ABBA blocks. The spatial multiplexing block Sspa is defined as s1 - s2 s3 1 - s4 si1 - si4 s an s4ns -3 s4ns -2 s4ns-1 - s4ns J s L s s 4 c J 26 which corresponds to the VBLAST layer mapping in Table 2. The ABBA block is defined as abba abba abba Sabba LS1 S2 SB J 27 where every element of equation 27 is given by Cl abba SB sk 1 - sk 2 sk 3 - sk 4 rs 1 -sl-3 si-43 sk 2 sk 1 sk 4 sk 3 s 1 - sl - 2 s i4 sl-2 sk 3 - sk 4 sk 1 - sk 2 s 4 si-1 _sk 4 sk 3 sk 2 sk 1 J .si si4 _ 28 with l nS 4B k 4 B - 1 nS and B 1 2 . nB. Rewriting the system equation 24 as a linear dispersion code we have 132 Mobile and Wireless Communications Physical layer development and implementation yi1 n 1 V 2 r1 n 2 y 3 n 3 yr n. H spa H abba Kd 29 y 1 nn. nR yr n r R y 3 nR y L nR J L ì j expressed in compact form as Yld HldSld Nld 30 where HLD is a linear dispersion matrix with two blocks one corresponding to the V-BLAST layers and another to the ABBA layers. The V-BLAST block Hspu is given by TJ spa TTspa spa H1 1 H1 2 H1 ns H spa 31 spa spa HnR 1 HnR 2 H spa nR ns where for i 1 2 h 0 0 0 i j 0 - h- 0 0 H spa i j 0 1 j 0 hj 0 _0 0 0 - h j J 32 nR and j 1 2 ns The ABBA block Hbbd is itself a block matrix it is given by High-Rate Reliable Communications with Hybrid Space-Time Codes 133 abba abba abba H H H 1 1 1 2 1 ns H abba 33 abba abba abba nR 1 nR 2 nR ns where every element of .
