This work investigates Generalized Receiver Spatial Modulation (GRSM) in a massive MIMO downlink scenario over millimetre wave channels. While GRSM enhances spectral efficiency (SE) and reduces power consumption, indexing additional bits using the spatial dimension increases the vulnerability to detection errors. These errors primarily stem from thresholddependent spatial detection. We propose a novel predefined threshold computation method minimizing spatial detection errors, rigorously validated through the Maximum A Posteriori (MAP) criterion. Furthermore, we derive an analytical Average Bit Error Probability (ABEP) expression tailored for energy detection, exploiting inherent constellation energy distributions. The analytical derivation was validated via link-level simulations under two scenarios: (i) perfect spatial detection, and (ii) practical spatial detection. The results show spatial errors dominating overall performance, shifted from theoretical values by practical spatial detection using multiple thresholds for different energy levels in 16QAM. Crucially, an inverted error trend revealed between GRSM-4QAM and GRSM-16QAM, highlighting a tradeoff between error resilience, complexity, and energy efficiency.

This paper studies the Cramér-Rao bound (CRB) for burst-mode transmission synchronization of Single-Sideband Frequency Shift Keying (SSB-FSK). Based on the CRB computations of burst-mode CPM, for conventional double sided schemes, it was shown that it is possible to obtain an optimum training sequence that minimizes the CRBs simultaneously for the joint estimation of symbol timing, frequency offset, and carrier phase. However, due to the SSB-FSK non-antipodal alphabet, it is impossible to use the same optimum sequence to minimize the CRBs for all parameters simultaneously. Meanwhile, in this paper, we propose a new general training sequence that can minimize the sum of all CRBs for any binary SSB-FSK. The derived results can be helpful for data-aided (DA) synchronization of SSB-FSK modulation.

This study revokes the performance of continuous phase modulation (CPM) able to generate a single-sideband (SSB) spectrum directly. This signal is analyzed in terms of modulation indices, pulse lengths, and pulse widths, all of which affect error probability, bandwidth, SSB property, and receiver complexity. The error probability performance is based on an approximation of the minimum Euclidean distance. A numerical power spectral density calculation for this particular SSB modulation in terms of the modulation index is presented. Reasonable tradeoffs in designing modulation schemes have been proposed using multi-objective optimization to ensure sizable improvements in bit error rate (BER), spectral efficiencies, and complexity without losing the property of being a SSB signal. Performance comparisons are made with known CPM schemes, e.g., Gaussian Minimum Shift Keying (GMSK) and Raised Cosine based CPM (RC).

In this article, we address the problem of optimal joint power and resource allocation when Non-Orthogonal Multiple Access (NOMA) and Orthogonal Frequency Multiple Access (OFDMA) are combined for a hybrid downlink multiple access. First, an optimal solution of joint power and resource allocation minimizing the transmit power consumption, is obtained by rewriting the original optimization problem into an equivalent convex one and then by solving it by means of the well-known interior-point method. Second, we analyze the properties of the optimum, which are twofold; we show that at the optimum, the order of the users is preserved from one channel to another. Then, we derive a closed-form expression for the optimal power allocation in the particular case where all users have positive non-zero transmit powers in all channels.

In wireless networks, the cooperative diversity is an implicit form of space diversity commonly used when other conventional transmit diversity methods might not be practical. It was largely proved that cooperative transmission, where a source and a relay cooperate to communicate with a unique destination, is power‐efficient compared to the point‐to‐point transmission. However, the model considered when stating this conclusion is counting only the transmission power consumption. In this study, the authors study the effect of taking into account not only the transmission power at each transmission node but also the processing power consumed in each reception node on the overall end‐to‐end performance. They formulate the optimisation problem aiming to minimise the total power consumption in order to achieve a target performance constraint, where the total power consumption stands for the sum of the transmission power and the processing power consumed in the decoding (neglecting other forms of power consumption). The authors' analysis relies on the characterisation of an information‐theoretic bound on the decoding power of any modern code to achieve a specified bit error probability while operating at a certain gap from the capacity. As this bound is built on the sphere‐packing analysis, this study focuses on message‐passing decoders. Using this theoretical framework, the improvement of well‐known cooperative protocols over the original non‐cooperative point‐to‐point system system is reinvestigated in terms of total power consumption. Thanks to this theoretical framework, a new classification of the studied cooperative protocols is given revealing some surprising conclusions. In particular, the selective decode‐and‐forward protocol is no more constantly preferred to its simpler alternative, i.e. the decode‐and‐forward protocol.

In this paper, we study the effect of optimal power allocation on the performance of communication systems using hybrid-automatic repeat request (HARQ) protocols with a limited maximum number of transmission rounds. We formulate the optimization problem aiming to minimize the total average power consumption in order to achieve a target performance constraint, where the total power consumption stands for the sum of the transmission power and the processing power consumed in the decoding. Our analysis relies on the characterization of an information-theoretic bound on the decoding power of any modern code to achieve a specified bit error probability while operating at a certain gap from the capacity. As this bound is built on the sphere-packing analysis, the present study focuses on message-passing decoders. We find that the implementation of power-adaptive HARQ reduces the total average power consumption even when taking decoding power into consideration, compared with reference systems.

In this study, the authors consider a delay‐limited hybrid automatic repeat request (HARQ) protocol that makes use of incremental redundancy over the three‐node decode‐and‐forward relay fading channel where one source cooperates with a relay to transmit information to the destination. They provide an estimate of the diversity‐multiplexing tradeoff (DMT) at finite signal‐to‐noise ratio (SNR) based on tight bounds on outage probabilities for two channel models. The results for the long‐term quasi‐static channel highlight the distributed diversity, that is, the cooperative space diversity, and the HARQ coding gain, achieved by soft combining the successive transmitted punctured codewords via incremental redundancy. On the other hand, the results for the short‐term quasi‐static channel illustrate the diversity gains obtained, thanks to cooperative space diversity and time diversity, along with the HARQ coding gain. Using the DMT formulation, they show that equal power partitioning between the source and the relay nodes provides close to optimal performance. Furthermore, thanks to the extension of the finite‐SNR DMT to the finite‐SNR diversity‐multiplexing‐delay tradeoff, they show that, unlike the asymptotic SNR analysis, the ARQ delay, defined as the maximum number of retransmissions rounds, impacts the performance of the HARQ relay protocol for high effective multiplexing gain.

In cooperative networks, despite its simplicity, the decode-and-forward protocol suffers from the problem of error propagation when the source-relay channel is noisy. By forwarding erroneous decoded messages, the relay significantly degrades the diversity order of the system. One trivial solution was to restrict the use of decode-and-forward protocol to reliable source-relay transmissions. However, the forwarded messages from the relay can be seen as data correlated with that transmitted by the source. This property can be exploited in order to allievate the error propagation phenomenon. The problem of joint decoding of correlated sources is then directly transposed to the relay network. In this paper, we propose to exploit the potential correlation existing between the source and the relay messages in order to achieve enhanced end-to-end performance. Performance comparison with classical decoding of the decode-and-forward protocol is conducted especially under degraded source-relay channel conditions. We derive an analytical upper bound on the probability of error at the destination, which is verified by simulation results.

Hybrid automatic repeat request (HARQ) is a well-known technique for improving system throughput and link performance of wireless communication systems, including cooperative communication systems. In this paper, we exploit the limited feedback applied to the two-source turbo coded cooperation scheme to define a particular cooperative HARQ protocol, called two-level HARQ, where the decision on retransmission at each node is conditioned by two levels: first by the feedback from the destination and second by the feedback from the partner node. To evaluate the performance improvement of this cooperative HARQ system over the original turbo coded cooperation system in terms of frame error probability, we define the system retransmission gain. This gain serves as a decision parameter to determine the conditions under which the cooperative HARQ protocol is useful. Finally, optimal time resource allocation is explored, offering sizable performance improvements.

We derive bounds on the error probability of optimal and sub- optimal detectors in an uncoded decode-and- forward relay system with two correlated information sources. This setup is relevant to wireless sensor networks where nearby sensors collect spatially correlated data. We show that taking into account the source correlation at the relay and at the destination leads to significant performance gains. Simulation results corroborate the tightness of our analytical bounds.

Wireless networks can exploit an implicit distributed diversity by the use of cooperative systems thanks to the broadcast nature of the radio link. Cooperation leads to improvements in terms of throughput and/or performance and decreases the sensitivity to channel variations. In this paper, a practical approach for a two-user cooperative wireless network is proposed based on a particular hybrid automatic repeat request (HARQ) protocol and turbo coded cooperation. In particular, we propose a two-level ARQ protocol where decision on retransmission is conditioned by two levels; first by the feedback from the destination and second by the feedback from the partner node. The proposed two-level ARQ protocol, combined with turbo coded cooperation, is designed to guarantee inter-user channel improvement through the relay-level ARQ, and consequently better overall system performance and higher throughput by controlling retransmission at destination side.