290 research outputs found
Performance Analysis of Decode-and-Forward Relaying in Gamma-Gamma Fading Channels
Decode-and-forward (DF) cooperative communication based on free space optical
(FSO) links is studied in this letter. We analyze performance of the DF
protocol in the FSO links following the Gamma-Gamma distribution. The
cumulative distribution function (CDF) and probability density function (PDF)
of a random variable containing mixture of the Gamma- Gamma and Gaussian random
variables is derived. By using the derived CDF and PDF, average bit error rate
of the DF relaying is obtained.Comment: 3 pages, 1 figure, journa
Modify-and-Forward for Securing Cooperative Relay Communications
We proposed a new physical layer technique that can enhance the security of
cooperative relay communications. The proposed approach modifies the decoded
message at the relay according to the unique channel state between the relay
and the destination such that the destination can utilize the modified message
to its advantage while the eavesdropper cannot. We present a practical method
for securely sharing the modification rule between the legitimate partners and
present the secrecy outage probability in a quasi-static fading channel. It is
demonstrated that the proposed scheme can provide a significant improvement
over other schemes when the relay can successfully decode the source message.Comment: IEEE International Zurich Seminar on Communications, Feb. 201
Near-Capacity Irregular Convolutional Coded Cooperative Differential Linear Dispersion Codes Using Multiple-Symbol Differential Detection
We propose a novel near-capacity Multiple-Symbol Differential Decoding (MSDD) aided cooperative Differential Linear Dispersion Code (DLDC) scheme, which exhibits a high grade of system design flexibility in terms of the choice of activated relays and the DLDC's rate allocation. More specifically, the system has the freedom to activate a range of DLDCs depending on both the number of relays available in the network, as well as on their position, throughput and complexity considerations
Outage Analysis of Hybrid Satellite-Terrestrial Cooperative Network with Best Relay Selection
In this paper, we study the performance of a downlink hybrid satellite-terrestrial cooperative network. The decode-andforward scheme is used and a selection of the best relay terminal is implemented. In this proposed system, a two time-slot scenario is considered. The first time slot is used by the satellite for broadcasting the information to the terrestrial relays and the destination. In the second time slot, only the best relay which provides the maximal received signal-to-noise (SNR) ratio at the
destination is selected for forwarding the information. Then, both signals are combined using the maximum ratio combining (MRC) technique. The analytical expression of the outage probabiliy is evaluated and is then verified with the simulation. The results show that our analytical expression matched well to the simulation results at the high SNR regime
Ergodic capacity of the exponentially correlated slotted amplify and forward relay channel
In this paper we analyze the performance degradation of slotted amplify-and-forward protocol in wireless environments with high node density where the number of relays grows asymptotically large. Channel gains between source-destination pairs in such networks can no longer be independent. We analyze the degradation of performance in such wireless environments where channel gains are exponentially correlated by looking at the capacity per channel use. Theoretical results for eigenvalue distribution and the capacity are derived and compared with the simulation results. Both analytical and simulated results show that the capacity given by the asymptotic mutual information decreases with the network density
Relay Assisted Cooperative OSTBC Communication with SNR Imbalance and Channel Estimation Errors
In this paper, a two-hop relay assisted cooperative Orthogonal Space-Time
Block Codes (OSTBC) transmission scheme is considered for the downlink
communication of a cellular system, where the base station (BS) and the relay
station (RS) cooperate and transmit data to the user equipment (UE) in a
distributed fashion. We analyze the impact of the SNR imbalance between the
BS-UE and RS-UE links, as well as the imperfect channel estimation at the UE
receiver. The performance is analyzed in the presence of Rayleigh flat fading
and our results show that the SNR imbalance does not impact the spatial
diversity order. On the other hand, channel estimation errors have a larger
impact on the system performance. Simulation results are then provided to
confirm the analysis.Comment: 5 pages, 3 figures, IEEE 69th Vehicular Technology Conferenc
DMT Optimal On-Demand Relaying for Mesh Networks
This paper presents a new cooperative MAC (Medium Access Control) protocol called BRIAF (Best Relay based Incremental Amplify-and-Forward). The proposed protocol presents two features: on-demand relaying and selection of the best relay terminal. âOn-demand relayingâ means that a cooperative transmission is implemented between a source terminal and a destination terminal only when the destination terminal fails in decoding the data transmitted by the source terminal. This feature maximizes the spatial multiplexing gain r of the transmission. âSelection of the best relay terminalâ means that a selection of the best relay among a set of (m-1) relay candidates is implemented when a cooperative transmission is needed. This feature maximizes the diversity order d(r) of the transmission. Hence, an optimal DMT (Diversity Multiplexing Tradeoff) curve is achieved with a diversity order d(r) = m(1-r) for 0 †r †1
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