We propose and prove a theorem that allows the calculation of a class of functionals on Poisson point processes that have the form of expected values of sum-products of functions. In proving the theorem, we present a variant of the Campbell-Mecke theorem from stochastic geometry. We proceed to apply our result in the calculation of expected values involving interference in wireless Poisson networks. Based on this, we derive outage probabilities for transmissions in a Poisson network with Nakagami fading. Our results extend the stochastic geometry toolbox used for the mathematical analysis of interference-limited wireless networks.

This paper discusses the design requirements for enabling multiple simultaneous peer-to-peer communications in IEEE 802.11 asynchronous networks in the presence of adaptive antenna arrays, and proposes two novel access schemes to realize multipacket communication (MPC). Both presented solutions, which rely on the information acquired by each node during the monitoring of the network activity, are suitable for distributed and heterogeneous scenarios, where nodes equipped with different antenna systems can coexist. The first designed scheme, called threshold access MPC (TAMPC), is based on a threshold on the load sustainable by the single-node, while the second protocol, called signal-to-interference ratio (SIR) access MPC (SAMPC), is based on an accurate estimation of the SIR and on the adoption of low density parity check codes. Both protocols, which are designed to be backward compatible with the 802.11 standard, are numerically tested in realistic scenarios. Furthermore, the performance of the two schemes is compared to the theoretical one and to that of the 802.11n extension in a mobile environment.

We investigate the statistics of the number of time slots T that it takes a packet to travel through a chain of wireless relays. Derivations are performed assuming an interference model for which interference possesses spatiotemporal dependency properties. When using this model, results are harder to arrive at analytically, but they are more realistic than the ones obtained in many related works that are based on independent interference models. First, we present a method for calculating the distribution of T. As the required computations are extensive, we also obtain simple expressions for the expected value E[T] and variance Var[T]. Finally, we calculate the asymptotic limit of the average speed of the packet. Our numerical results show that spatiotemporal dependence has a significant impact on the statistics of the travel time T. In particular, we show that, with respect to the independent interference case, E[T] and Var[T] increase, whereas the packet speed decreases.

Multiple‐input multiple‐output (MIMO) techniques have received a considerable attention from the research community for their promising performance in faded environments, and particular interest has been given to the physical (PHY) layer implications of the tradeoff between multiplexing and diversity. This study discusses this tradeoff extending the analysis to the medium access control (MAC) layer. To this purpose, a theoretical model for assessing the performance of an 802.11 network that relies on a MIMO‐enabled PHY layer is presented. The proposed model characterises the different MIMO systems in terms of their multiplexing gain and bit error rate performance, considering both the diversity gain of the specific MIMO scheme and the impact of the spatial distribution of the nodes. The results compare, from a MAC layer perspective, the benefits of multiplexing and diversity, providing some analytic insights on the tradeoff between increasing the system's reliability and enhancing the data rate of the single link.

This paper analyzes the performance of an 802.11 network in which spatial reuse enables the simultaneous coexistence of multiple asynchronous communications between different node pairs. This scenario, defined multi-packet communication (MPC), is theoretically investigated by deriving the capture probability for the single communication and by evaluating the network throughput using a Markov chain approach. The mechanisms introduced in the analysis for MPC operations enable the development of an improved version of the 802.11 access scheme, whose performance is evaluated using a reliable simulation platform. The main purpose of this study is to directly compare the throughput obtained from the completely theoretical analysis of an MPC scenario with that obtained from a protocol implementation, discussing some issues related to the accuracy of the collision model in realistic network topologies.

We show by means of stochastic geometry that interference dynamics has a strong impact on the performance of cooperative relaying. For both conventional and multi-hop-aware cooperative relaying we show that the packet delivery probability significantly changes with the dependence of interference among the links. Depending on the scenario under consideration, this change could be either an increase or decrease of the packet delivery probability. Especially for multi-hop-aware cooperative relaying, the performance gain is heavily reduced when interference possesses high temporal and spatial dependence.

Cooperative MAC protocols have been shown to increase the attainable network throughput and to reduce the outage probability when perfect Channel State Information (CSI) is available either at the source station or at candidate relays. This paper investigates the realistically achievable network performance of relay selection schemes under imperfect CSI knowledge. Novel relay selection algorithms, based on a Markov Decision Process (MDP) framework, are proposed for mitigating the performance degradation introduced by imperfect channel knowledge. We demonstrate that the performance of cooperative MAC schemes crucially depends on the accuracy of the CSI knowledge. Furthermore, it is shown that the Markov framework allows the source station to predict the channel quality and hence to reduce the number of transmission errors, ultimately resulting in an improved network performance.

The Space-Time Shift Keying (STSK) framework subsumes diverse Multiple-Input Multiple-Output (MIMO) schemes, offering a near-capacity performance at a reduced complexity. The STSK system's performance crucially depends on the dispersion matrix (DM) set used for encoding the transmitted symbols. We introduce a novel criterion, based on EXtrinsic Information Transfer (EXIT) chart analysis, for selecting capacity-approaching sets from candidate DMs, and a novel Genetic Algorithm (GA) for efficiently exploring the search space formed by the candidate DM sets. Our proposed GA allows obtaining DM sets that enhance the system's performance compared to a random selection, while simultaneously reducing the search algorithm's complexity.

Cooperation has been recently introduced to mitigate the impairments imposed by fading on a communication channel. A cooperative transmission, in which the destination may overhear all transmission attempts, benefits from incremental redundancy techniques, achieving a higher throughput and reducing the packet delay and the outage probability. This paper presents a theoretical framework to assess the limiting performance of efficient coding techniques in Decode-and-Forward cooperative scenarios. In this paper it is shown that suitable designed codes, such as punctured turbo codes, approach the limiting performance in all the studied scenarios. The paper also addresses the design of punctured turbo code schemes capable of performing close to the presented limiting bound. A novel Genetic Algorithm (GA) is introduced for designing incremental puncturing schemes suited to cooperative transmissions. The algorithm uses a recently proposed tri-dimensional (3D) EXtrinsic Information Transfer (EXIT) chart technique to model the decoding behavior of parallel concatenations of non-systematic periodically punctured convolutional codes. It is shown that the design algorithm allows contriving capacity approaching codes for the source and the relay. The paper further shows that the GA aided designed codes closely approach the theoretical results, outperforming previously proposed systematic incremental and complementary schemes.

Cross-layer designed cooperative Medium Access Control (MAC) protocols for 802.11 wireless networks have been recently shown to achieve a better performance than the Distributed Coordination Function (DCF). This paper analyses the effects of different channel coding techniques on the performance of cooperative MAC protocols. Different forwarding schemes, inspired by Hybrid Automatic Repeat and reQuest (HARQ) techniques, are evaluated, and some guidelines are given to design codes suited to cooperative MAC protocols. Furthermore, the cooperative network's saturation throughput and average packet delay are theoretically evaluated using the sphere-packing bound and extending the Markov models used for 802.11 networks. The model is validated performing bit by bit simulations of the cooperative MAC schemes, showing that the theoretical limiting performance are closely approached by efficient coding schemes.

Recent studies have shown that designing a Medium Access Control (MAC) protocol combined with a cooperative approach may improve the attainable network throughput, despite reducing the mean packet delay. In this paper we design a MAC scheme adopting cooperative physical layer aided cross-layer techniques. We consider a popular cooperative MAC protocol, namely the CoopMAC technique of Liu et al., which is improved by facilitating cooperative signal combining at the destination and employing two relays in the context of a successive relaying technique. The performance of the proposed scheme is evaluated by Monte-Carlo simulations. We demonstrate that a cross-layer design further improves the performance gain provided by the CoopMAC protocol over that of the legacy 802.11 Distributed Coordination Function (DCF), enhancing both the achievable network throughput and the outage probability.