We consider a simultaneous wireless transfer of information and power in a two-way relaying network, where a decode-and-forward protocol is employed for data exchange between two source devices at different rates. The data exchange is accomplished in two time phases (TPs) with possibly asymmetric TP ratios, where the relay is powered by the source devices in the first phase through simultaneous wireless information and power transfer (SWIPT) either by power splitting (PS) or by time switching (TS). For the network, resource allocation of the PS and TP ratios for the PS-based SWIPT and that of the TS and TP ratios for the TS-based SWIPT are studied to minimize the system outage probability. We first solve the joint optimization problem of each case with the instantaneous channel state information and then propose suboptimal schemes utilizing one or two values for the TP ratio to lower the implementation complexity. The results from analysis and simulation show that the proposed schemes outperform the benchmark scheme with equal resource allocation and that the gain gets more prominent as the rates of the data exchanged or the relay locations become more asymmetric.

A novel scheme called the selective mapping of partial tones (SMOPT) is addressed for the reduction of the peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. The SMOPT first produces a set of modified OFDM symbols with reduced PAPRs by adding a set of mapping symbols designed on peak reduction tones (PRT) to the original OFDM symbol. The SMOPT then selects the symbol with the lowest PAPR for transmission among the modified OFDM symbols. When simulated under the IEEE 802.11a wireless local area network and ETSl EN 300 401 digital audio broadcasting physical layer models, the SMOPT is observed to have lower sensitivity to PRT positions, lower complexity, and more design flexibility than the tone reservation scheme.

A generalized observation model for signal detection problems is proposed. The model allows consideration of several interesting special cases including additive noise, multiplicative noise, and signal-dependent noise, and includes both deterministic and random signals. Locally optimum (LO) detectors are interesting generalizations of those for the additive noise model. Under the proposed observation model the performance of the LO detectors is compared with that of other common detectors

We consider a two-way relay (TWR) network with multiple relays, where the relays adopt physical layer network coding based on decode-and-forward. A joint relay selection and power allocation (RS-PA) scheme is proposed to improve the symbol error probability (SEP) of the TWR network using BPSK modulation under the total power constraint. For the proposed scheme and the benchmark scheme performing RS without PA, the average SEP of the TWR network is derived analytically and confirmed with simulation results. It is shown that the proposed scheme provides an asymptotic SNR gain of about 1.76 dB over the benchmark scheme at the same diversity order.