This work presents a new cross‐layer cooperative medium access control (CMAC) protocol with hybrid radio frequency (RF) energy‐harvesting (EH) capability to enhance the energy efficiency and network lifetime of energy‐constrained wireless ad‐hoc networks. The proposed protocol employs an adaptive transmission process and integrates the hybrid time–power splitting wireless EH technique at the relay node. The relay node can also assist using its own power (traditional cooperation) provided its battery level is sufficiently adequate and there is no need for RF‐EH. The best transmission mode among direct transmission, cooperative transmission and TPSR cooperation is selected based on power allocation. Two techniques namely the outage probability quality‐of‐service requirement and transmit power optimisation are considered. In addition, the distributed relay selection process is proposed to select the best helper based on location, residual energy and EH information that can significantly enhance the energy efficiency and network lifetime of the wireless network. The results indicate that the proposed protocol can extend the lifetime and improves the energy efficiency of the network.

This study analyses the performance of a three‐node cooperative relaying system with single amplify‐and‐forward fixed‐gain relay. In most works, the source‐to‐destination ( SD ) link under deep fade condition is ignored. However, the link may experience a severe fading condition which can still contribute partially towards system diversity. Therefore, the authors assume that SD link undergoes severe fading (i.e. Weibull fading with severity parameter less than two), while the other asymmetric fading channels of the source‐to‐relay and the relay‐to‐destination links are subjected to Weibull and Rician fading, respectively. The derivations of analytical expressions for cumulative distribution function and probability density function of the instantaneous output signal‐to‐noise ratio at the destination terminal, allow the evaluation of outage probability, bit error probability with their diversity order of the particular system design. From the results, at a certain Weibull severity level, the SD link can be omitted and considered as deep fade since it offers insignificant diversity order.

Partial transmit sequence (PTS) is an effective scheme to reduce high peak‐to‐average power ratio (PAPR) for multicarrier modulation (MCM) signal transmission systems. This approach produces side information (SI) data as a result of the MCM signal optimisation process. The generated SI data are required to be transmitted with the original data over the channel for successful data recovery at the receiver. An effective method for SI data transmission has not yet been identified and research is still ongoing. Hence, the authors introduce a technique that embeds SI data into the original data frame. In this study, a wavelet packet (WP)‐based PTS (WP‐PTS) scheme is selected as the MCM transmission method. The proposed scheme is called WP‐PTS with embedded SI data. In addition, a suitable scheme for reconstructing the original data is developed. Simulation result shows that the PAPR performance of the proposed scheme improves by up to 2.5 dB at a complementary cumulative distribution function level of 10 −4 compared with the original WP‐orthogonal frequency‐division multiplexing system without the PAPR reduction scheme when the number of selected disjoint subblocks is 16.

This paper presents a multiuser detection technique using compressive sensing (CS) where the entries data entries of finite-alphabet signals are considered as sparse data. Thus the proposed system is underdetermined, which pave the way for the usage of lattice sphere decoding (LSD) technique. In order to demonstrate the effectiveness of the proposed method, it is tested at different sparsity levels. We show that the proposed method provides substantial performance gain over the previous work.

The scalar Nt× NrMIMO system can be designed as the Nt independent SISO transmitters, where Ntand Nrare the number of transmit and receive antennas, respectively. Each of the transmitters has an independent symbol mapper, which rotates the phase according to the phase of the channel from its antenna to the receiver reference antenna. Every symbol mapper assigns a maximum degree of freedom to the signal, which in turn requires the minimum feedback bits. The Nr received signals reform the same transmit constellation after applying the combining vector of the GMRC (Generalized Maximum Ratio Combining) receiver. The Wireless open-Access Research Platform (WARP) is employed for prototyping and testing these transmitters. The empirical results of a frame transmission reflect the theory and validate the codebooks. However, the hardware-based imperfections and the channel estimation errors affect the performance of the frame. The former errors are originated from a non-ideal time synchronization, Automatic Gain Control (AGC), Analogue to Digital Converters (ADCs) and Digital to Analogue Converters (DACs). The channel estimations are done prior to the frame transmission. However, empirically, the estimated channels are not constant during the frame transmission, and there are fluctuations in their phases and magnitudes. These fluctuations are intensive when there is a line of sight (LOS) path between the antennas. It is shown that codebooks with a low number of feedback bits perform better than those with a large number of feedback bits in this situation.

Multiple description (MD) coding has been a popular choice for robust data transmission over the unreliable network channels. Lattice vector quantization provides lower computation for efficient data compression. In this paper, a new MD coinciding lattice vector quantizer (MDCLVQ) is presented. The design of the quantizer is based on coinciding 2-D hexagonal sublattices. The coinciding sublattices are geometrically similar sublattices, with the same index but generated by different generator matrices. A novel labeling algorithm based on the hexagonal coinciding sublattices is also developed. Performance results of the MDCLVQ scheme, together with the new labeling algorithm applied to standard test images, show improvements of the central and side decoders, as compared with the renowned techniques for several test images.

Almost of the cooperative technique have been assumed that the selection users for certain group are predetermined based on location of users in cell and channel conditions between users. However, it is important to develop the efficient algorithms for assigning the terminals with good inter-user channels for cooperating groups. This paper develop coupling algorithm involve optimal partner, since introduce short time for processing and performance of the asymptotic compared with exhaustive search. Numerical results show that the partner coupling algorithm provides the similar average user outage probability to the partner selection algorithm using exhaustive search. Also the average user outage probability of Reed Solomon (RS) coded cooperation increases with the number of users.

In this paper a new adaptive subband thresholding algorithm is introduced for finding the optimize threshold values of the subbands. The search technique is exhaustive, where the distortion level and bit allocation are used as the limiting factors. The algorithm is applied in multistage lattice VQ (MLVQ) to enhance the PSNR performance. The MLVQ image coding technique reduces the quantization error of the quantized vectors by "blowing out" the residual quantization errors with a LVQ scale factor. Experimental results for images using the adaptive subband thresholding technique and the MLVQ are shown to be superior to those of JPEG2000 for a set of test images