Rate adaptation is an effective approach to achieve high spectrum efficiency under varying channel condition, especially for wireless communication. This paper proposes rate adaptation at receiver for wireless relay s...Rate adaptation is an effective approach to achieve high spectrum efficiency under varying channel condition, especially for wireless communication. This paper proposes rate adaptation at receiver for wireless relay system. In this scheme, source node uses a new modulation technology, called random projections code (RPC), to achieve rate adaptation. Both relay node and destination node decode the received RPC encoding signals. If destination does not decode RPC correctly, relay node will act compressing and forwarding role by performing LDPC syndrome encoding and sending syndrome coded information to destination node. We discuss how to jointly decode at destination node when it receives RPC coded information from source node and syndrome coded information from relay node. Finally, we evaluate the scheme by bit-error-rate (BER) and good put evaluation metrics. Simulation results show that the coding gain is about 4 dB, 3.1 dB, 2.2 dB and 1.6 dB for LDPC coding rate 0.8, 0.89, 0.94, 0.99 at BER 10-5 respectively. The throughput of the schemes is at least 0.3 bit/s/Hz higher than RPC at SNR ranging from 5 dB to 25 dB.展开更多
The performance of downlink multiple-input multiple-output (MIMO) cellular networks is limited by co-channel interference (CCI). In this paper, we propose a linear precoding scheme based on signal-to-leakage-and-noise...The performance of downlink multiple-input multiple-output (MIMO) cellular networks is limited by co-channel interference (CCI). In this paper, we propose a linear precoding scheme based on signal-to-leakage-and-noise ratio (SLNR) criteria which can reduce the CCI significantly. Since each user’s SLNR value is corresponding to the largest eigenvalue of the generalized matrix which indicates the channel quality that we propose a scheme to do a dynamic power allocation as an auxiliary way to improve SLNR precoding scheme. We use the perturbation theory to update each user’s SLNR value each time step in time-varying channels rather than directly decompose the channel matrix so as to reduce the amount of calculation. The simulation results show that the proposed scheme offers about 0.3 bps/Hz additional capacity gain and 0.5 dB BER gain over conventional SLNR precoding method with lower computational complexity. And it also obtains about 0.5 bps/Hz additional capacity gain and 1 dB BER gain compared to the scheme only update the preceding vectors.展开更多
文摘Rate adaptation is an effective approach to achieve high spectrum efficiency under varying channel condition, especially for wireless communication. This paper proposes rate adaptation at receiver for wireless relay system. In this scheme, source node uses a new modulation technology, called random projections code (RPC), to achieve rate adaptation. Both relay node and destination node decode the received RPC encoding signals. If destination does not decode RPC correctly, relay node will act compressing and forwarding role by performing LDPC syndrome encoding and sending syndrome coded information to destination node. We discuss how to jointly decode at destination node when it receives RPC coded information from source node and syndrome coded information from relay node. Finally, we evaluate the scheme by bit-error-rate (BER) and good put evaluation metrics. Simulation results show that the coding gain is about 4 dB, 3.1 dB, 2.2 dB and 1.6 dB for LDPC coding rate 0.8, 0.89, 0.94, 0.99 at BER 10-5 respectively. The throughput of the schemes is at least 0.3 bit/s/Hz higher than RPC at SNR ranging from 5 dB to 25 dB.
文摘The performance of downlink multiple-input multiple-output (MIMO) cellular networks is limited by co-channel interference (CCI). In this paper, we propose a linear precoding scheme based on signal-to-leakage-and-noise ratio (SLNR) criteria which can reduce the CCI significantly. Since each user’s SLNR value is corresponding to the largest eigenvalue of the generalized matrix which indicates the channel quality that we propose a scheme to do a dynamic power allocation as an auxiliary way to improve SLNR precoding scheme. We use the perturbation theory to update each user’s SLNR value each time step in time-varying channels rather than directly decompose the channel matrix so as to reduce the amount of calculation. The simulation results show that the proposed scheme offers about 0.3 bps/Hz additional capacity gain and 0.5 dB BER gain over conventional SLNR precoding method with lower computational complexity. And it also obtains about 0.5 bps/Hz additional capacity gain and 1 dB BER gain compared to the scheme only update the preceding vectors.
