JOURNAL OF APPLIED SCIENCES Electronics and Information Engineering TP (2012)

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1 JOURNAL OF APPLIED SCIENCES Electroics ad Iformatio Egieerig Vol. 30 No. 1 Ja. 01 DOI: /j.iss OFDM 1, 1,, 1, OFDMAF amlify ad forward P (01) Resource Otimizatio for Fairess ad Sum Rate radeoff i Multiuser OFDM-Based wo-way Relayig ANG Lu 1, LIU Ji 1, LI Guo-ju, CHEN Qia-bi 1, WANG Guag-yu 1 1. Key Laboratory of Mobile Commuicatio echology, Chogqig Uiversity of Posts ad elecommuicatios, Chogqig , Chia. Deartmet of Commuicatio Commadig, Chogqig Commuicatio Istitute, Chogqig , Chia Abstract: I OFDM-based cooerative two-way relay etworks, sum rate ad fairess amog user airs caot be achieved simultaeously whe these user-airs exchage their iformatio resectively via a amlify-adforward two-way relay. his aer rooses a ovel subotimal resource allocatio scheme to trade off the roortioal fairess ad the system sum rate. his scheme is divided ito two stes to maximize the sum rate of the system subject to the costraits of total ower ad roortioality amog user-air data rate. First, sub-carrier otimizatio is rocessed with equal ower amog every subcarrier to achieve roortioal fairess ad imrove the system sum rate. o further imrove the sum rate while maitaiig fairess, the total ower is allocated to every sub-carrier with a iterative ower allocatio algorithm. Simulatio demostrates that the roosed scheme of resource allocatio ca achieve good tradeoff betwee roortioal fairess ad system sum rate. Keywords: OFDM, two-way relayig, roortioal fairess, sub-carrier otimizatio, ower otimizatio. 4. [1. [ (No.011ZX ) (No , No ) (No.CSC009BA090) (No.KJ100514) (No.A011-) (No.A011-10) tagl@cqut.edu.c cheqb@cqut.edu.c

2 (orthogoal frequecy divisio multile access, OFDM). OFDM OFDM. OFDM [4-6. [4-5 1 [6.. OFDM. [7. [8. [9 OFDMA. OFDM. 1 OFDM 1 M k B k (k 1,, M). OFDM N. (multile-access, MA) (broadcast, BC). MAOFDMA(orthogoal frequecy divisio multile access). h f B k B k x x B k B k, 1 OFDM Figure 1 System model for multiuser OFDM-based two-way relayig B k B k. B k k (k 1,, M) yk h x + B k fb k x B k + k (1) k (additive white Gaussio oise, AWGN). BC yk B k. R [10 ηk R ( h ) + f () + 1 (time divisio dulexig, DD) B k y η k h y k + (3) y B k η k f B k y k + B k (4) B k B k η k h x η k f x.. B k (chael state iformatio CSI) CSI CSI. B k y η k h B k f B k x B k + η k h k + (5)

3 1 OFDM 41 y B k η k f B k h x + η k f B k k + B k (6) B k γ γ B k γ γ B k R R h R f B k h + h + f (7) + 1 R h fb k f + h + f (8) + 1 k Rk 1 [ ( ) ( ) lb 1 + γ + lb 1 + γ (9) 1. t k {0, 1} k t k 1 t k 0. M 1. t k k1 OFDM M R t krk (10) k1 1 (10) t k. OFDM. P 1 subject to max {t k,, R, } R M t k 1 k1 M k1 1 t krk R 1 : R : : R k χ 1 : χ : : χ k M ( R + + ) B k P 1 k1 1 t k (11) P Rk k χ1 : χ : : χk R....1 (k, ) (k, ) P max {, R, } R k subject to + R + B k (1) [5 KK P 1 1 [1 + f 1 + f + [ 1 + h [ 1 + f B k [ 1 + h [ 1 + f B k (13) 1 + f + [ 1 + h [ 1 + f R (14) (15) (13) (15) (7) (8) B k γ γ B k γa k γb k γk 1 ( ) h f + h [ + f [ h 1 + (16) f

4 4 30 P max Rk max γ k h fb k.. 1, arg max t,k γ k k (17) 0,. P 1 R1 : R : : Rk χ1 : χ : :χk 1 Rk 0 k Ω k S( S). for k 1 : M i arg max γk i ti k 1 i k Rk Ω k Ω k i S S i. 3 S arg mi k R k k arg χ k max γ j k j S k. Rk Ω k Ω k j S S j.. (16) (k, ) Rk. P 3 subject to max R 1 P 1 0 R k R1 : R : : Rk χ1 : χ : : χk (18) P 3. P 3 P 4 max R R k subject to P (19) λ P 4 f(λ) max 0 L P 4 max 0 1 ( N ) Rk λ P 1 L P 4 P 4 ( N ) L P 4 Rk λ P 1 subject to 0 1 (0) (1) N f (λ) max 0 [R k λ () f (λ) f (λ) + λp (3) 1 g (λ) mi f (λ) (4) λ 0 (3) λ P 4 P R d g (λ ) R 0. d 0 [1. P 4 N [13 P 3. (4). N. λ [11 () P [ 1 λ ( ) h + f + h f (5)

5 1 OFDM 43 (x) + max {0, x}. λ [ ( + λ (t + 1) λ (t) + µ P ) (6) 1 t µ. µ t λ [14. λ (5) P. (13) (15) B k R.. P 3 R1 : R : : Rk χ1 : χ : : χk P 1 for k 1 : M R / k χk R χ 1 R / k χk R χ > 1 k. k τ P τp. τ τ 3. P R k. ( K R ) /( ( k Rk ) ) 3 F K 1 k1 χ k χ k. R1 : R : : Rk χ1 :χ : :χk F F ( K R ) /( ( k Rk ) ) K F k1 χ k χ k F > F. P (13) (15) B k R. 3 5 MHz 64 OFDM. γ P ( γ P ). h v 1 / d l f v /(1 d) l v i i 1, 0 1. d 1 d d 0 1. l l P. R1 : R : R3 : R41:1:1:1... P Figure Achieved sum rate versus total ower 3 4 d 4 P 60 W.. 3 R1 : R : R3 : R41:1:1:1.. 4 R1 : R : R3 : R41:::..

6 (R1 :R :R3 :R41:1:1:1) Figure 3 Comariso of fairess ad rate amog each user-air(r1 :R :R3 :R41:1:1:1) 4 (R1 :R :R3 :R41:::) Figure 4 Comariso of fairess ad rate amog 4 each user-air(r1 :R :R3 :R41:::) OFDM.... : [1 Shao C E. wo-way commuicatio chaels [C//Proceedigs of 4th Berkeley Symosium o Mathematical Statistics ad Probability, Califoria, America, 1961: [ Ahlswede R, Cai N, LI S Y R, YEUNG R W. Network iformatio flow [J. IEEE rasactios o Iformatio heory, 000, 46(4): [3 [J. 009, 3(1): Yag Bo, Yu Hogyi, Lü Lig, Feg Qiag. Hig sectral efficiet bi-directioal successive relayig techiques [J. Joural of Beijig Uiversity of Posts ad elecommuicatios, 009, 3(1): (i Chiese) [4. [J. 010, 3(4): Zhao Rui, Fu Youhua, Li Chuguo, Yag Lüxi. Relay rocessig ad resource allocatio stratrgies for multi-atea two-way relay system [J. Joural of Electroics & Iformatio echology, 010, 3(4): (i Chiese) [5 Ho C K, Zhag Rui, Yig Chaglig. wo-way relayig over OFDM: otimized toe ermutatio ad ower allocatio [C//IEEE Iteratioal Coferece o Commuicatios, Beijig, Chia, May 008: [6 Jag Y U, Jeog E R, Lee Y H. A two-ste aroach to ower allocatio for OFDM sigals over two-way amlify-ad-forward relay [J. IEEE rasactios o Sigal Processig, 010, 58(4): [7 Kommate J, Zhag R, Liag Y C. Otimal resource allocatio for two-way relay-assisted OFDMA [J. IEEE rasactios o Vehicular echology, 009, 58(4): [8 Shi H, Lee J H. Subcarrier allocatio for multiuser two-way OFDMA relay etworks with fairess costraits [C//Vehicular echology Coferece, 010: 1-5. [9. OFDMA [J. 011, 9(): ag Lu, Jiag Guagjia, Che Qiabi. Low comlexity resource allocatio i OFDMA-based decode-ad-forward relayig etworks [J. Joural of Alied Scieces, 011, 9(): (i Chiese) [10 Rakov B, Wittebe A. Sectal efficiet rotocols for half-dulex fadig relay chaels [J. IEEE Joural o Selected Areas i Commuicatios, 007, 5(): [11 Dog M, Shahbazaahi S. Otimal sectrum sharig ad ower allocatio for OFDM-based twoway relayig [C//IEEE Iteratioal Coferece o Acoustics, Seech ad Processig USA: IEEE Press, 010: [1 Yu Wei, Lui R. Dual methods for ocovex sectrum otimizatio of multicarrier systems [J. IEEE rasactios o Commuicarios, 006, 54(4): [13 Boyd S, Vadeberghe L. Covex otimizatio [M. Cambridge, UK: Cambridge Uiversity Press, 004. [14 Bertsekas D. Noliear rogrammig [M. d ed. Belmot, MA: Athea Scietific, ( : )