Turbo Receiver Design for MIMO Relay ARQ Transmissions

Transcription

1 Turbo Receiver Design for MIMO Relay ARQ Transmissions Halim Yanikomeroglu Carleton University, Canada A joint work with Zakaria El-Moutaouakkil (Telecom Bretagne, France) Tarik Ait-Idir (ExceliaCom Solutions, Morocco) Samir Saoudi (Telecom Bretagne, France) Global Communications Conference (GLOBCOM) th December 2012 Zakaria El-Moutaouakkil (NSN, Morocco) October 3, Receiver 2012 Design for Throughput-Efficient Relay ARQ Transmissions (1)

2 Outline Cooperative Communications 1 Cooperative Communications Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (2)

3 Progress of wireless communications Progress of wireless communications 5G Requirements Impacting on Physical Layer Constraints posed by 3G & 4G 1G : (1980s 1990s) wireless communications were based on analogue systems. 2G : (1990s 2000) such systems as GSM and IS-95 were defined, these systems were essentially designed for voice and low data rate applications. 3G : ( ) it addresses costumer demands for high-speed data communications while the business focus has shifted from voice services to multimedia communication applications over Internet. 4G : (Next few months) moving from standardization to deployment phase with the promise of providing faster and more affordable wireless Internet connectivity. 5G (beyond-4g)!? Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (3)

4 5G Requirements Impacting on Physical Layer Progress of wireless communications 5G Requirements Impacting on Physical Layer Constraints posed by 3G & 4G Very high bit rates (e.g. 100 Mb/s to 1 Gb/s) with high user densities. Ubiquitous coverage. Adaptive and self configuring to user needs and transmission environment. Moderate cost: terminal cost, power and battery requirements commensurate with required performance and data rate. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (4)

5 5G Requirements Impacting on Physical Layer Progress of wireless communications 5G Requirements Impacting on Physical Layer Constraints posed by 3G & 4G Very high bit rates (e.g. 100 Mb/s to 1 Gb/s) with high user densities. Ubiquitous coverage. Adaptive and self configuring to user needs and transmission environment. Moderate cost: terminal cost, power and battery requirements commensurate with required performance and data rate. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (4)

6 5G Requirements Impacting on Physical Layer Progress of wireless communications 5G Requirements Impacting on Physical Layer Constraints posed by 3G & 4G Very high bit rates (e.g. 100 Mb/s to 1 Gb/s) with high user densities. Ubiquitous coverage. Adaptive and self configuring to user needs and transmission environment. Moderate cost: terminal cost, power and battery requirements commensurate with required performance and data rate. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (4)

7 5G Requirements Impacting on Physical Layer Progress of wireless communications 5G Requirements Impacting on Physical Layer Constraints posed by 3G & 4G Very high bit rates (e.g. 100 Mb/s to 1 Gb/s) with high user densities. Ubiquitous coverage. Adaptive and self configuring to user needs and transmission environment. Moderate cost: terminal cost, power and battery requirements commensurate with required performance and data rate. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (4)

8 5G Requirements Impacting on Physical Layer Progress of wireless communications 5G Requirements Impacting on Physical Layer Constraints posed by 3G & 4G Very high bit rates (e.g. 100 Mb/s to 1 Gb/s) with high user densities. Ubiquitous coverage. Adaptive and self configuring to user needs and transmission environment. Moderate cost: terminal cost, power and battery requirements commensurate with required performance and data rate. Goal enabling the 4A paradigm any rate, anytime, anywhere, affordable Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (5)

9 5G Requirements Impacting on Physical Layer Progress of wireless communications 5G Requirements Impacting on Physical Layer Constraints posed by 3G & 4G Very high bit rates (e.g. 100 Mb/s to 1 Gb/s) with high user densities. Ubiquitous coverage. Adaptive and self configuring to user needs and transmission environment. Moderate cost: terminal cost, power and battery requirements commensurate with required performance and data rate. Cooperative Relaying Concept Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (6)

10 5G Requirements Impacting on Physical Layer Progress of wireless communications 5G Requirements Impacting on Physical Layer Constraints posed by 3G & 4G Very high bit rates (e.g. 100 Mb/s to 1 Gb/s) with high user densities. Ubiquitous coverage. Adaptive and self configuring to user needs and transmission environment. Moderate cost: terminal cost, power and battery requirements commensurate with required performance and data rate. Cooperative Relaying Concept Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (6)

11 Progress of wireless communications 5G Requirements Impacting on Physical Layer Constraints posed by 3G & 4G Constraint posed by 3G & 4G mobile terminals infeasible!? Tx H Rx Relay H Rx Mobile Terminal Base Station Tx MT BS 3 3 MIMO System 3 3 Virtual MIMO System In cellular Networks, it is not feasible to deploy several antennas at our mobile terminals!! Solution Virtual MIMO has been proposed. Cooperative Communication Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (7)

12 Progress of wireless communications 5G Requirements Impacting on Physical Layer Constraints posed by 3G & 4G Constraint posed by 3G & 4G mobile terminals infeasible!? Tx H Rx Relay H Rx Mobile Terminal Base Station Tx MT BS 3 3 MIMO System 3 3 Virtual MIMO System In cellular Networks, it is not feasible to deploy several antennas at our mobile terminals!! Solution Virtual MIMO has been proposed. Cooperative Communication Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (7)

13 Model Brief Description of the Concept Relay ARQ Protocol Relay ARQ with Slot Mapping Reversal Sub-Packets ARQ Transmission Model NR NS Source Relay 1 2 ARQ 3 Fig. 1: Model. ND Destination Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (8)

14 Brief Description of the Concept Brief Description of the Concept Relay ARQ Protocol Relay ARQ with Slot Mapping Reversal Sub-Packets ARQ Transmission Model NR NS Source Relay 1 2 ARQ 3 ND Destination Fig. 1: Model Channel 1, channel 2, and channel 3 are regarded at kth transmission as a frequency selective fading MIMO channels having L SR, L RD, and L SD independent paths, respectively. Each path is characterized by its quasi-static flat fading MIMO channel matrix H AB(k) l C N A N B, for l {0,..., L AB 1} where A {S, R} and B {R, D}. Relaying works under the framework of half-duplex amplify-and-forward protocol. Packet re-transmissions follows the Chase-type ARQ mechanism. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (9)

15 Brief Description of the Concept Brief Description of the Concept Relay ARQ Protocol Relay ARQ with Slot Mapping Reversal Sub-Packets ARQ Transmission Model NR NS Source Relay 1 2 ARQ 3 ND Destination Fig. 1: Model Channel 1, channel 2, and channel 3 are regarded at kth transmission as a frequency selective fading MIMO channels having L SR, L RD, and L SD independent paths, respectively. Each path is characterized by its quasi-static flat fading MIMO channel matrix H AB(k) l C N A N B, for l {0,..., L AB 1} where A {S, R} and B {R, D}. Relaying works under the framework of half-duplex amplify-and-forward protocol. Packet re-transmissions follows the Chase-type ARQ mechanism. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (9)

16 Brief Description of the Concept Brief Description of the Concept Relay ARQ Protocol Relay ARQ with Slot Mapping Reversal Sub-Packets ARQ Transmission Model NR NS Source Relay 1 2 ARQ 3 ND Destination Fig. 1: Model Channel 1, channel 2, and channel 3 are regarded at kth transmission as a frequency selective fading MIMO channels having L SR, L RD, and L SD independent paths, respectively. Each path is characterized by its quasi-static flat fading MIMO channel matrix H AB(k) l C N A N B, for l {0,..., L AB 1} where A {S, R} and B {R, D}. Relaying works under the framework of half-duplex amplify-and-forward protocol. Packet re-transmissions follows the Chase-type ARQ mechanism. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (9)

17 Brief Description of the Concept Brief Description of the Concept Relay ARQ Protocol Relay ARQ with Slot Mapping Reversal Sub-Packets ARQ Transmission Model NR NS Source Relay 1 2 ARQ 3 ND Destination Fig. 1: Model Channel 1, channel 2, and channel 3 are regarded at kth transmission as a frequency selective fading MIMO channels having L SR, L RD, and L SD independent paths, respectively. Each path is characterized by its quasi-static flat fading MIMO channel matrix H AB(k) l C N A N B, for l {0,..., L AB 1} where A {S, R} and B {R, D}. Relaying works under the framework of half-duplex amplify-and-forward protocol. Packet re-transmissions follows the Chase-type ARQ mechanism. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (9)

18 Brief Description of the Concept Brief Description of the Concept Relay ARQ Protocol Relay ARQ with Slot Mapping Reversal Sub-Packets ARQ Transmission Model Fig. 2: Source node transmitter scheme. Splitting Rule Upon the 1 st transmission, node S generates according to an STBICM encoder the symbol packet x [x 0,..., x T 1 ] C N S T. (1) It is then splitted into two equally sized N S T 2 sub-packets z1 and z2 constructed as { z 1,t = x 2t, 0 t T 2 1 z 2,t = x 2t+1, 0 t T 2 1. (2) Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (10)

19 Brief Description of the Concept Brief Description of the Concept Relay ARQ Protocol Relay ARQ with Slot Mapping Reversal Sub-Packets ARQ Transmission Model Fig. 2: Source node transmitter scheme. Splitting Rule Upon the 1 st transmission, node S generates according to an STBICM encoder the symbol packet x [x 0,..., x T 1 ] C N S T. (1) It is then splitted into two equally sized N S T 2 sub-packets z1 and z2 constructed as { z 1,t = x 2t, 0 t T 2 1 z 2,t = x 2t+1, 0 t T 2 1. (2) Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (10)

20 Relay ARQ Protocol Cooperative Communications Brief Description of the Concept Relay ARQ Protocol Relay ARQ with Slot Mapping Reversal Sub-Packets ARQ Transmission Model Trans. (k) 1 st TS 2 nd TS Trans. (k odd) 1 st TS 2 nd TS Trans. (k even) 1 st TS 2 nd TS (S) Z1 Z2 (S) Z1 Z2 Z2 Z1 (R) y R (k) y R (k) (R) y R (k) y R (k) y R (k) y R (k) (D) y D 1,(k) y D 2,(k) (D) y D 1,(k) y D 2,(k) y D 1,(k) y D 2,(k) (a) (b) Transmission Period Reception Period Fig. 3: Relay ARQ Protocol (a), Relay ARQ with Slot-Mapping Reversal (b) for k = 1,..., K. Sub-Packets Slot Mapping is Fixed Fig. 3(a) z 1 followed by z 2 during the first and the second TS, respectively, for all the ARQ rounds. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (11)

21 Relay ARQ with Slot Mapping Reversal Brief Description of the Concept Relay ARQ Protocol Relay ARQ with Slot Mapping Reversal Sub-Packets ARQ Transmission Model Trans. (k) 1 st TS 2 nd TS Trans. (k odd) 1 st TS 2 nd TS Trans. (k even) 1 st TS 2 nd TS (S) Z1 Z2 (S) Z1 Z2 Z2 Z1 (R) y R (k) y R (k) (R) y R (k) y R (k) y R (k) y R (k) (D) y D 1,(k) y D 2,(k) (D) y D 1,(k) y D 2,(k) y D 1,(k) y D 2,(k) (a) (b) Transmission Period Reception Period Fig. 3: Relay ARQ Protocol (a), Relay ARQ with Slot-Mapping Reversal (b) for k = 1,..., K. Sub-Packets Slot Mapping is Reversed Fig. 3(b) Depending on the transmission index parity, sub-packets z 1 and z 2 are mapped onto either the first or the second time slot. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (12)

22 Sub-Packets ARQ Transmission Model (I) During the 1 st TS of ARQ round k: Brief Description of the Concept Relay ARQ Protocol Relay ARQ with Slot Mapping Reversal Sub-Packets ARQ Transmission Model y (k) R,t = L SR 1 E SR H SR(k) l z 1,(t l)mod T + n (k) R,t (3) 2 l=0 y 1,(k) D,t = L SD 1 E SD H SD(k) 1,l z 1,(t l)mod T + n 1,(k) D,t (4) 2 l=0 E SR and E SD are the energies capturing the effects of path loss and shadowing in channel 1 and 3, respectively. n (k) B,t N (0 N B 1, N 0I NB ) for B {R, D}. A cyclic prefix (CP) portion of length L cp = max {L SD, L SR, L RD } is appended to z 1 and z 2 upon their transmission. AF function at the Relay node: { ỹ (k) R,t = γy(k) R,t, t = 0,..., T 2 1 γ = 1/ N S E SR + N 0 (5) Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (13)

23 Sub-Packets ARQ Transmission Model (II) Brief Description of the Concept Relay ARQ Protocol Relay ARQ with Slot Mapping Reversal Sub-Packets ARQ Transmission Model During the 2 nd TS of ARQ round k: y 2,(k) D,t = Lmax 1 l=0 H (k) l z (t l)mod T 2 + ñ 2,(k) D,t (6) where [ ] z 1,t z t X 2N S, z 2,t L max max(l SD, L SRD ), and L SRD = L SR + L RD 1, [ H (k) l = γ E SR E RD H SRD(k) l ] ESD H SD(k) 2,l, (7) ñ 2,(k) D,t = γ E RD L RD 1 l=0 H RD(k) l n (k) R,(t l)mod T + n 2,(k) D,t. (8) 2 Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (14)

24 Sub-Packets ARQ Transmission Model (III) Brief Description of the Concept Relay ARQ Protocol Relay ARQ with Slot Mapping Reversal Sub-Packets ARQ Transmission Model At the end of the second slot node D builds up (jointly) the augmented size signal vector {[ ] 1,(k) Lmax 1 y y equ(k) D,t D,t ỹ 2,(k) = H equ(k) l z (t l)mod T + n equ(k) D,t, (9) D,t 2 l=0 in which the k-parity 2N D 2N S equivalent MIMO channel matrix H equ(k) l has been carefully introduced with the following form [ ] H equ(k) A 0 ND N l = S, k odd B C [ ] (10) H equ(k) 0 ND N l = S A, k even C B where, A = E SD H SD(k) 1,l, (11) B = γ E SR E RD L 1 H SRD(k) l, (12) C = E SD L 1 H SD(k) 2,l. (13) Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (15)

25 Sub-Packets ARQ Transmission Model (III) Brief Description of the Concept Relay ARQ Protocol Relay ARQ with Slot Mapping Reversal Sub-Packets ARQ Transmission Model In a joint manner signal vector y equ(k) D,t is grouped with all the previously received signals y equ(k 1) D,t,, y equ(1) D,t to decode the data packet. K ARQ rounds Transmission Model This leads to the 2N D k 2N s block transmission model given by y equ(1) D,t H equ(1) n equ(1) Lmax 1 l D,t. = z. (t l)mod T + 2 y equ(k) l=0.. (14) D,t H equ(k) l n equ(k) D,t }{{}}{{}}{{} y equ,k H equ,k D,t l n equ,k D,t Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (16)

26 Outage Probability Cooperative Communications Outage Probability Average Throughput Definition (Pertaining to K=1) The outage probability at a given signal-to-noise ratio (SNR) ρ, denoted by P out, refers to the probability half of the information rate I (the factor 1 2 comes from the fact that one channel use of the equivalent received signal model (9) corresponds to two temporal channel uses), between transmitted block z and received block y equ,1, is below a target rate R, D { 1 ( { } ) } P out (ρ, R) = Pr 2 I z; y equ,1 H equ,1 D l, ρ < R (15) where z = z 1. z T2, and yequ,1 D = y equ,1 D,1. y equ,1 D, T 2 1. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (17)

27 Outage Probability Cooperative Communications Outage Probability Average Throughput Generalization To extend the previous formula on our ARQ relay system, we use the renewal theory as well as the observation that allows us to view the presented Chase-type ARQ mechanism, with a maximum number of rounds K, as a repetition coding scheme over K parallel sub-virtual channels. Accordingly, given the equivalent MIMO-ARQ channel model (14), (15) can be re-written as { 1 ( P out (ρ, R) =Pr 2K I z; y equ,k D { H equ,k l } ) }, ρ < R, A 1,..., A K 1, where A k represents the event that a NACK feedback is sent back to the source node S at round k = 1,..., K 1. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (18)

28 Average Throughput Cooperative Communications Outage Probability Average Throughput The average throughput formula corresponding to the transmission over the equivalent Relay ARQ MIMO channel is given by η = E [R] E [ν]. (16) R is a discrete random variable equals either to R when successful packet decoding is detected within the K rounds or 0 otherwise. In an outage sense, these two values are taken with probabilities 1 P out (ρ, R) and P out (ρ, R), respectively. ν is a RV counting the number of rounds consumed to transmit one packet. Thus, the average throughput (16) can be re-expressed as where R ν = R/E [ν]. η = R ν (1 P out (ρ, R)) (17) Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (19)

29 Scenario 1 Cooperative Communications Outage Probability Average Throughput Outage Probability Relay ARQ with SMR K=2 Relay ARQ K=2 Relay ARQ K=1 Reference Protocol Direct Transmission K=2 Direct Transmission K= SNR(dB) Fig. 4: Outage probability versus SNR for l SR = 0.3, N S = N R = N D = 2, L SR = L RD = L SD = 3, and κ = 3. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (20)

30 Scenario 2 Cooperative Communications Outage Probability Average Throughput Outage Probability Relay ARQ with SMR K=2 Relay ARQ K=2 Relay ARQ K=1 Reference Protocol Direct Transmission K=2 Direct Transmission K= SNR(dB) Fig. 5: Outage probability versus SNR for l SR = 0.7, N S = N R = N D = 2, L SR = L RD = L SD = 3, and κ = 3. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (21)

31 Scenario 1 Cooperative Communications Outage Probability Average Throughput Average Throughput (bit/s/hz) Relay ARQ with SMR K=2 Relay ARQ K=2 Relay ARQ K=1 Reference Protocol Direct Transmission K=2 Direct Transmission K= SNR(dB) Fig. 6: Average throughput versus SNR for l SR = 0.3, N S = N R = N D = 2, L SR = L RD = L SD = 3, and κ = 3. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (22)

32 Scenario 2 Cooperative Communications Outage Probability Average Throughput Average Throughput (bit/s/hz) Relay ARQ with SMR K=2 Relay ARQ K=2 Relay ARQ K=1 Reference Protocol Direct Transmission K=2 Direct Transmission K= SNR(dB) Fig. 7: Average throughput versus SNR for l SR = 0.7, N S = N R = N D = 2, L SR = L RD = L SD = 3, and κ = 3. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (23)

33 Key Ideas Cooperative Communications Key Ideas Turbo Receiver Design One time slot additional set of N S transmit and N D receive antennas at node S and Node D, respectively. One packet re(transmission) additional set of 2N D receive antennas at node D. Our relay ARQ system at round k virtual 2N D k 2N S MIMO system Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (24)

34 Soft Sub-Packet Combiner Derivation Key Ideas Turbo Receiver Design At ARQ round k, the N D kt N S T sub-packet ARQ transmission model is gen by y equ,k = H equ,k z + n equ,k, (18) where x = clmn (z t) = clmn (xt) 0 t T t T 1 y equ,k = clmn (y equ,k 0 t T 2 1 D,t ) n equ,k = clmn 0 t T 2 (n equ,k D,t ). (19) H equ,k can be block-diagonalized in the Fourier basis as H equ,k = U H T /2,2N D k (k) U T /2,2NS k. (20) Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (25)

35 Soft Sub-Packet Combiner Derivation Key Ideas Turbo Receiver Design Applying the DFT to both sides of (18) yields the following multi-round frequency domain (FD) sub-packet ARQ transmission model y equ,k f = (k) x f + n equ,k f. (21) Unconditional MMSE Filter x (k) f = Φ (k) y equ,k Ψ (k) x f f The forward filter Φ (k) = diag { { Φ (k) 0,, Φ(k) T /2 1 } }, and the backward filter Ψ (k) = diag Ψ (k) 0,, Ψ(k) are respectively expressed, for t = 0,, T/2 1, T /2 1 as { } Φ k t = 1 N (k)h 0 t I 2ND k + (k) t C 1 t (k)h t C 1 1 t = N 0 Θ(k) x + (k)h t (k). t Ψ k t = Φ(k) t (k) t 2 T /2 1 T i=0 Φ (k) t (k) t Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (26)

36 Key Ideas Turbo Receiver Design Building Blocks of the Proposed Receiver virtual second slot ND receive antennas CP deletion ARQ round 1 soft sub-packet combiner soft de-mapper soft mapper de-interleaver interleaver + + SISO decoder CRC b CP deletion previous rounds received signals and CFRs ACK/NACK feedback ARQ round k Fig. : Building blocks of the proposed turbo receiver. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (27)

37 Recursive Implementation (Algorithm) Key Ideas Turbo Receiver Design { } Two recursive variables: ỹ equ,k and Γ (k) = diag Γ (k) t 0,, Γ(k) are introduced T /2 1 within the following new soft sub-packet combining structure where x (k) f = Φ (k) ỹ equ(k) f ỹ equ(k) = ỹ equ(k 1) f f ỹ equ(0) = 0 2NS 1 f Γ (k) t = Γ (k 1) t + Υ (k)h t Υ (k) t Γ (0) t = 0 2NS 2N S Ψ (k) x f, (22) + Υ (k)h y equ(k) f The backward-forward filters have been adjusted to Φ (k) = diag and Ψ { } (k) = diag Ψ(k) (k) 0,, Ψ with T /2 1 { Φ (k) t = 1 N I 2NS Γ (k) 0 t C 1 } t C i = N 0 Θk 1 x + Γ (k) t Ψ (k) (k) t = Φ t Γ (k) t 2 T /2 1 T t=0 Φ (k) t Γ (k) t. { } Φ(k) (k) 0,, Φ, T /2 1. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (28)

38 Scenario 1 Cooperative Communications Average Throughput Average Throughput (bits/s/hz) Relay ARQ with SMR CR-Selective DF CR-AF Scenario SNR(dB) Fig. 6: Average throughput versus SNR for l SR = 0.3, N S = N R = 2, N D = 3, L SR = L RD = L SD = 3, and κ = 3. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (29)

39 Scenario 2 Cooperative Communications Average Throughput 2.0 Scenario 2 Average Throughput (bits/s/hz) Relay ARQ with SMR CR-Selective DF CR-AF SNR(dB) Fig. 7: Average throughput versus SNR for l SR = 0.6, N S = N R = 2, N D = 3, L SR = L RD = L SD = 3, and κ = 3. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (30)

40 Conclusion Cooperative Communications Conclusion Perspectives New throughput-efficient relay ARQ techniques are investigated. The half-duplex constraint has been turned from a disadvantage causing a multiplexing gain loss to an advantage providing significant improvement in average throughput & outage probability performance. Relay ARQ with SMR along with signal-level turbo sub-packet combining provides considerable gain in average throughput compared with conventional ARQ-based cooperative relaying over the entire SNR region. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (31)

41 Conclusion Cooperative Communications Conclusion Perspectives New throughput-efficient relay ARQ techniques are investigated. The half-duplex constraint has been turned from a disadvantage causing a multiplexing gain loss to an advantage providing significant improvement in average throughput & outage probability performance. Relay ARQ with SMR along with signal-level turbo sub-packet combining provides considerable gain in average throughput compared with conventional ARQ-based cooperative relaying over the entire SNR region. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (31)

42 Conclusion Cooperative Communications Conclusion Perspectives New throughput-efficient relay ARQ techniques are investigated. The half-duplex constraint has been turned from a disadvantage causing a multiplexing gain loss to an advantage providing significant improvement in average throughput & outage probability performance. Relay ARQ with SMR along with signal-level turbo sub-packet combining provides considerable gain in average throughput compared with conventional ARQ-based cooperative relaying over the entire SNR region. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (31)

43 Perspectives Cooperative Communications Conclusion Perspectives Analytical results of the outage probability and average throughput instead of Monte-Carlo based simulations should be investigated. Extension of the proposed techniques to a multi-user environment where several relays are deployed. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (32)

44 Perspectives Cooperative Communications Conclusion Perspectives Analytical results of the outage probability and average throughput instead of Monte-Carlo based simulations should be investigated. Extension of the proposed techniques to a multi-user environment where several relays are deployed. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (32)

45 Perspectives Cooperative Communications Conclusion Perspectives Analytical results of the outage probability and average throughput instead of Monte-Carlo based simulations should be investigated. Extension of the proposed techniques to a multi-user environment where several relays are deployed. Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (32)

46 Cooperative Communications Zakaria El-Moutaouakkil, Tarik Ait-Idir, Halim Yanikomeroglu, and Samir Saoudi, Receiver Design for Throughput-Efficient MIMO Relay ARQ Transmissions, to be submitted, IEEE Transactions on Signal Processing, 30 pp., December Hatim Chergui, Tarik Ait-Idir, Mustapha Benjillali, Zakaria El-Moutaouakkil, and Samir Saoudi, Joint-Over-Transmissions Project and Forward Relaying for Single Carrier Broadband MIMO ARQ Systems, submitted, IEEE Vehicular Technology Conference VTC-Spring 2011, Budapest, Hungary, May Zakaria El-Moutaouakkil, Tarik Ait-Idir, Halim Yanikomeroglu, and Samir Saoudi, Relay ARQ Strategies for Single Carrier MIMO Broadband Amplify-and-Forward Cooperative Transmission, in Proc., 21th Annual IEEE Symposium on Personal Indoor and Mobile Radio Communications PIMRC 2010, Istanbul, Turkey, Sep Tarik Ait-Idir, Houda Chafnaji, and Samir Saoudi, Turbo Packet Combining for Broadband Space-Time BICM Hybrid-ARQ Systems with Co-Channel Interference, IEEE Transactions on Wireless Communications, vol. 9, no. 5, pp , May Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (33)

47 Perspectives & Conclusion Thank you very much Zakaria El-Moutaouakkil (NSN, Morocco) Receiver Design for Throughput-Efficient Relay ARQ Transmissions (34)