Bandwidth Efficiency Analysis for Cooperative Transmission Methods of Downlink Signals using Distributed Antennas In this paper, the performance of cooperative transmission methods for downlink transmission is analyzed for distributed antenna systems, where the base station (BS) and remote antennas (RA) are connected through wireline or dedicated channels. In particular, for the open-loop and closed-loop transmission based on the availability of the channel state information (CSI) at the transmitter, the SIR and average bandwidth efficiency for different cooperative transmission methods are derived, and an effective cooperative transmission strategy for given locations of the mobile station (MS) is proposed. Keywords: Distributed antennas, Signal-to-Interference ratio, Bandwidth efficiency, MRT, EGT, STBC I
h[ L1 h 1 L h ] (1) h 1 RA i L i RA i x i P x w wx
III L1 h 1 x 1 L h x IΣ N i1,im,n L i h i x i I Σ N i1,im,n L i P P 1 L 1 h 1 P P L h P x 1 t 0, t 1 (t 0 T s ) y 0 L1 h 1 x 1 L h x I (4) y 1 L1 h 1 x * L h x * 1I (5) * T s x 1 L1 h * 1 y 0 L h y * 1 (L 1 h 1 L h )x 1 L1 h * 1 I L h I * (6) x L h * y 0 L1 h 1 y * 1 (L 1 h 1 L h )x L1 h 1 I * L h * I (7) P 1 P γ STBC (8) N y L1 h 1 x 1 Σ L i h i x i () i3 w P 1 γ SAT (3) w 1 h H w [ ] (9) w 1 h H
RA 1 RA SIR x1 P 1 L 1 h * 1 x 1 L 1 h 1 L h L h * x 1 L 1 h 1 L h P 1 P h * 1 x 1 h 1 h * x 1 h ( P1 P ) time t: time t: time tt s : L 1 h * 1 x 1 L 1 h 1 L h time tt s : L h * x L 1 h 1 L h P 1 P (P 1 P ) L 1 h * 1 ( x* ) L 1 h 1 L h L 1 h * x* 1 L 1 h 1 L h time t: x 1 time tt s : x * time t: x time tt s : x * 1 P 1 P x 1 wwx 1 (L 1 h 1 L h ) yhwx 1 I x1 I (10) L 1 h 1 L h yhwx 1 I( L1 h 1 L h )x 1 I (13) ( P1 P ) γ EGT (14) P 1 P γ MRT (11) w 1 h 1 h H w [ ] [ ] (1) w 1 h 1 h x L1 h * 1 0 x 1 x [ ][ ] (15) L 1 h 1 L h 0 L h * x* x* 1 t 0, t 1 (t 0 T s )
L 1 h 1 x 1 L h x * y 0 I (16) L 1 h 1 L h P 1 P γ STBCT (0) (P 1 P ) L 1 h 1 x L h x * 1 y 1 I (17) L 1 h 1 L h α L1 h 1 L 1 h 1 L h β L h L 1 h 1 L h x 1 αy 0 βy* 1 (L 1 h 1 ) (L h ) x 1 αiβi * (18) L 1 h 1 L h x βy 0 αy* 1 (L 1 h 1 ) (L h ) x αiβi * (19) L 1 h 1 L h IV
P 1 P P 1 P P P P 1 5P1 P 1 5P1 () lim P1 P (P 1 P ) =P 1 lim P1 P (P 1 P )((P 1 P ) )=P 1 lim P1 P ( P1 P ) =P 1 lim P1 P (P 1 P ) =P 1 ( P1 P ) P 1 P (1) (P 1 P ) P 1 P P P 1 5P1 P 1 5P1 P P 1 5P1 P 1 5P1 P 1 P
L 1 h 1 x 1 f γ SAT (γ) exp ( γ ) (3) σ 1 σ 1 L 1 h 1 x 1 L h x σ 1 σ π k f γ STBC (γ)σ exp ( γ ) (4) k1 σ k σ k π k Π k k1, kk σ k (σ k σ k ) σ 1 σ
π k f γ MRT (γ)σ exp ( γ ) (5) k1 σ k σ k π k Π k k1, kk σ k (σ k σ k ) γ E[η STBC ] 0 log (1γ)f γ STBC (γ)dγ 1 σ I σ I { σ 1 exp ( ) Ei ( (σ 1 ) σ )ln σ 1 σ 1 σ exp ( ) Ei ( )} (8) σ σ ηlog (1γ) (6) E[η SAT ] 0 log (1γ)f γ SAT (γ)dγ σ I exp ( ) Ei ( σ 1 σ 1 ) (7) ln E[η MRT ] 0 log (1γ)f γ MRT (γ)dγ 1 σ I σ I { σ 1 exp ( ) Ei ( (σ 1 ) σ )ln σ 1 σ 1 σ exp ( ) Ei ( )} (9) σ σ E[] Ei(z) -z e t t dt
η η η η η η V
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