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In this letter, we develop a new precoding scheme that improves the performance of mutual information for generalized spatial modulation (GSM). First, the closed-form expression of the mutual information of the GSM with finite alphabet inputs is derived in order to update the precoder with regard to the mutual information. The joint precoding design problem to maximize the mutual information of the...
In this paper, we propose an adaptive power allocation method for hybrid relay systems that employ the amplify-and-forward and decode-and-forward protocols simultaneously. The total transmission power is analytically allocated to a source and two selected relays by the proposed power allocation criterion to maximize the overall received signal-to-noise ratio at the destination. Simulation results...
In this paper, a multi-user beamforming scheme is presented in multi-user multi-input multi-output (MIMO) downlink channels with other cell interference (OCI). The proposed scheme consists of maximizing signal-to-leakage-and-noise ratio (SLNR) and whitening the OCI for power allocation. The conventional scheme which eliminates perfectly intra-cell interference has several problems such as antenna...
We propose an improved timing estimation method for orthogonal frequency-division multiplexing (OFDM) systems that employ a preamble with time-domain repetitive patterns. The proposed method exploits the unique correlation property of the preamble including its cyclic prefix. Numerical results show that the proposed scheme is robust in fading multipath channels, achieving better performance than the...
Hybrid relay systems using Amplify-and-Forward protocol (AF) and Decode-and-Forward protocol (DF) together are introduced in cooperative networks. For hybrid systems, we propose adaptive relay selection scheme to maximize the overall received Signal to Noise Ratio (SNR) at the destination. At first two relays are selected among many according to the instantaneous channel conditions. One is a relay...
An adaptive resource assignment scheme for the multi-user cooperative communication systems with amplify-and-forward (AF) relays is investigated. We consider maximizing system capacity while guaranteeing the QoS (Quality of Service) of each user. A resource assignment is proposed using space-time coding with only source-to-relay channel gain information (CGI). It performs well in allocating relay...
An adaptive relay allocation scheme for multi-user cooperative communication systems with amplify-and-forward (AF) relays is investigated. We consider maximizing system capacity while guaranteeing the QoS (Quality of Service) of each user. Proposed relay allocation scheme uses space-time coding technique. It performs well in allocating relay nodes to multiple source-destination pairs. The proposed...
A novel method is proposed that can estimate the tag population in radio frequency identification systems by using a Hadamard code for the sub-preamble of the tag response. We formulate the maximum likelihood estimator for the tag population using a given number of the observed footprints. In simulations, the proposed estimator performs considerably better than the conventional schemes.
In this paper, the analysis of an average received signal-to-noise ratio (SNR) for a cooperative communication network with amplify-and-forward (AF) relays is presented. In AF systems, the overall instantaneous SNR at the receiving end can be expressed as the form of a harmonic mean of per-hop SNRs. This means that the received SNR can be analyzed by applying the statistical expectation of the harmonic...
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