Non-cooperative Scheme Research Articles

Interference Channels With Full-Duplex Amplify-and-Forward Receiver Cooperations

This paper considers a two-transmitter and two-receiver interference channel (IC), where each transmitter sends a message to its desired receiver. In particular, the full-duplex (FD) amplify-and-forward (AF) protocol is adopted to build up the receiver cooperations: each receiver can receive the signals from the two transmitters and two receivers, and after self-interference (SI) cancellation and message decoding, it forwards them to its counterpart. With the above scheme, the equivalent channel model is analyzed, and the statistics of the accumulated residual interference and noise (ARIN), generated by the imperfect SI cancellation and the AF scheme at the receivers, is calculated by mathematical induction. Then, the achievable rate regions of both the single-user and joint decoding schemes are derived. It is proved that one-side cooperation, i.e., only one of the two receivers forwards its counterpart’s signal, is optimal to achieve the best system performance. Next, to characterize the obtained rate regions, the rate maximization problems are formulated and approximately solved by a sequential parametric convex approximation (SPCA) method. Simulation results show that the proposed scheme can improve the achievable rate compared to the conventional non-cooperative scheme in several typical scenarios.

A Hierarchical Clustering Algorithm for Interference Management in Ultra-Dense Small Cell Networks

Ultra-dense small cell networks (UD-SCNs) will be an integral part of next generation network (NGN). How to deal with serious interference is one of the important challenges in a UD-SCN. In this paper, the cooperative interference management problem for a UD-SCN is explored by allowing small cell base stations (SBSs) to collaborate with their neighbors. The proposed coalitional structure generation among SBSs can mitigate the co-tier interference within a coalition, thus improving the network capacity. Specifically, a cooperative scheme among the neighboring SBSs is formulated as a coalitional structure generation with characteristic forms. Furthermore, the relative sub-channel resources are allocated in the process of cluster generation. Compared with the existing SBS cooperative schemes, the novelty of the proposed SBS cooperation method, which uses a hierarchical clustering algorithm (SC-HCA) to compute the pairs of members, is demonstrated. The computation can enhance the efficiency of the proposed algorithm and is especially suitable for UD-SCN scenarios with tens and even hundreds of cells. The simulation results show that the proposed SC-HCA achieves a 422.13% system data rate improvement relative to that of the non-cooperative scheme in a UD-SCN scenario.

DSWIPT Scheme for Cooperative Transmission in Downlink NOMA System

In this paper, we focus on the issue how to reduce the throughput performance gap between a cell-center user and a cell-edge user in a two-user downlink non-orthogonal multiple access (NOMA) system. To this end, we propose a dynamic Simultaneous Wireless Information and Power Transfer cooperative NOMA (DSWIPT NOMA) scheme. In the proposed scheme, the cell-center user works as a relay to improve the throughput performance of the cell-edge user. The relaying operation is powered by the DSWIPT scheme, in which both the time allocation (TA) ratio and power splitting (PS) ratio can be adjusted dynamically to make full use of the time/power resource in each transfer frame. Specifically, the analytical expressions of the outage probability (OP) corresponding to the cell-center user and the cell-edge user are derived. And a joint optimization algorithm is also proposed to find the optimal TA ratio and PS ratio for maximizing the sum-throughput of the system. The numerical results show that the analytical results are in accordance with the Monte-Carlo simulation results exactly. Compared with the non-cooperative NOMA scheme and the SWIPT cooperative NOMA scheme, the DSWIPT NOMA scheme has a better performance in both the sum-throughput of the system and the OP of the cell-edge user.

Distributed Wideband Sensing-Based Architecture for Unlicensed Massive IoT Communications

Providing Internet connectivity to a massive number of Internet-of-Things (IoT) objects over the unlicensed spectrum requires: 1) identifying a very large number of narrowband channels in a wideband spectrum and 2) aggressively reusing the available channels over space to accommodate the high density of IoT devices. To this end, we propose a sensing-based architecture that identifies spectral and spatial resources at a fine resolution. In particular, we first propose a sensing assignment scheduler, where each base station (BS) is assigned a subset of the spectrum to sense at a high resolution. We then propose a distributed sensing algorithm, where BSs locally process and share their sensing reports, so that each BS obtains occupancy information of the wideband spectrum at its location. Once the spatio-spectral resource blocks are identified, we further propose a distributed resource allocation algorithm that maintains high spatial reuse of spectral opportunities while limiting the intra-network and inter-network interference. Numerical simulations are presented to validate the effectiveness of the proposed distributed algorithms, comparing them to centralized and non-cooperative schemes. It is shown that our architecture identifies more spatio-spectral resources, with lower misdetection of incumbents. As a result, more IoT devices are connected with limited interference into incumbents.

Multiple relay‐based Reed–Muller network‐coded cooperation for wireless communication system

This research article proposes a multiple relay-based Reed–Muller network-coded cooperative (MR-RMNCC) scheme for wireless communication. In the MR-RMNCC scheme, Hadamard transform construction is adopted to build Reed–Muller (RM) codes that effectively achieve network coded-cooperation among multiple sources and multiple relays over slow and fast Rayleigh fading channels. In any network coded-cooperative system, a proper encoding strategy at the relay nodes is vital for achieving an optimum code construction at the destination node. Therefore, the authors have proposed an efficient message bit selection algorithm at relay-2 that optimally selects the message bits. The supremacy of the message bit selection algorithm is demonstrated by Monte–Carlo simulation. Furthermore, the performance bound for average error-probability is also derived for the MR-RMNCC scheme that validates its simulated bit-error-rate performance over a fast Rayleigh fading channel. At the destination node, the MR-RMNCC scheme is jointly decoded by two different decoding strategies, i.e. joint soft maximum likelihood decoding and joint majority logic decoding. Monte–Carlo simulations suggest that the MR-RMNCC scheme not only provides a significant bit-error-rate performance gain over its corresponding coded non-cooperative scheme but also to the existing state-of-the-art RM network-coded cooperative scheme under identical conditions.

Ultrawideband Network Channel Models for Next-Generation Wireless Avionic System

This paper proposes an impulse radio ultrawideband (IR-UWB) wireless network channel model for next-generation wireless avionic system (NGWAS). Complexities such as poor network localization, redundant wiring, network security flaws, suitable physical proximity to the aircraft system's controller and need to guarantee scalable wireless network access have necessitated the adoption of wing system units of a passenger aircraft for this scheme's deployment. The proposed IR-UWB approach aims at alleviating the attendant drawbacks by selecting optimal channel path from available paths on the basis of bit error rate (BER), based on the numerical results obtained from the Saleh–Valenzuela (S-V) principle. Cooperative relay transmission schemes factored upon transmission power, overall outage probability and spectral-energy efficiency tradeoffs for the relay network communication were also investigated and compared with the noncooperative schemes. Simulation results validate maximum data packet delivery while a strong network signal strength is attained. Comparative approach of the performances of the IR-UWB standardized channel models are also evaluated.

Cellular Cooperative Unmanned Aerial Vehicle Networks With Sense-and-Send Protocol

In this paper, we consider a cellular controlled unmanned aerial vehicle (UAV) network in which multiple UAVs cooperatively complete each sensing task. We first propose a sense-and-send protocol where the UAVs collect sensory data of the tasks and transmit the collected data to the base station. We then formulate a joint trajectory, sensing location, and UAV scheduling optimization problem that minimizes the completion time for all the sensing tasks in the network. To solve this NP-hard problem efficiently, we decouple it into three subproblems: 1) trajectory optimization; 2) sensing location optimization; and 3) UAV scheduling. An iterative trajectory, sensing, and scheduling optimization (ITSSO) algorithm is proposed to solve these subproblems jointly. The convergence and complexity of the ITSSO algorithm, together with the system performance are analyzed. Simulation results show that the proposed ITSSO algorithm saves the task completion time by 15% compared to the noncooperative scheme.

Cooperative Multi-Sender Index Coding

In this paper, we propose a new coding scheme and establish new bounds on the capacity region for the multi-sender unicast index-coding problem. We revisit existing partitioned Distributed Composite Coding (DCC) proposed by Sadeghi et al. and identify its limitations in the implementation of multi-sender composite coding and in the strategy of sender partitioning. We then propose two new coding components to overcome these limitations and develop a multi-sender Cooperative Composite Coding (CCC). We show that CCC can strictly improve upon partitioned DCC, and is the key to achieve optimality for a number of index-coding instances. The usefulness of CCC and its special cases is illuminated via non-trivial examples, and the capacity region is established for each example. Comparisons between CCC and other non-cooperative schemes in recent works are also provided to further demonstrate the advantage of CCC.

Cooperative Multi-Path Routing Solution With Real-Time Optimization for Streaming Application Using Auction Theory

Cooperation among network devices is a promising approach to improve network throughput and network service quality. In addition, it can be used to enhance network survivability against failures. In this paper, we study a cooperative multi-path routing solution for wireless Users Equipment (UEs)’ streaming applications. We assume that UEs use multi-path transport layer service, and establish two paths for streaming, one path goes through its cellular link, and the other path is established using a Wi-Fi connection with a neighbor UE. We study a user coordinated multi-path routing solution with two different energy cost functions, a Linear Cost Function (LCF) and Energy As the Cost (EAC) and design user cooperative real-time optimization and failure protection operations for the streaming application. To stimulate UEs to participate in the user cooperation operation, we design a credit system enabled by an auction mechanism. We compare the performance of user cooperation schemes to the non-cooperative scheme, and using simulation results show that applying the proposed user cooperation scheme and establishing multi-path connections for streaming has an advantage in improving the service rate and streaming success rate, and reduces energy consumption compared to non-cooperation solutions. User cooperation scheme with LCF energy cost function can also help balance the energy consumption among UEs in the system compared to user cooperation scheme with EAC energy cost function.

Amplify-and-Forward Relaying Based Spectrum Sharing in Both Time and Spectrum Domains With Wireless Powered Primary User

We propose a spectral and energy efficient cooperative spectrum sharing scheme with the primary user (PU) capable of harvesting wireless energy. Along with an access point (AP) transferring wireless power to PU, a secondary source (SS) and a secondary relay (SR) can cooperatively transmit data to a secondary destination (SD) using the amplify-and-forward protocol. The interference from secondary transmissions can boost the amount of harvested energy at PU. After the wireless power transfer phase, PU transmits data to AP using the harvested energy, and meanwhile SS transmits data to SD. The SR could simultaneously forward the data of both systems to improve their communication qualities. With the energy and data cooperations from SS and SR, more energy can be harvested by PU and the data reception at AP becomes more reliable, so the throughput performance of primary system can be satisfied more easily. As a result, a fraction of spectrum could be enough for the primary system and the remaining spectrum is released to the secondary system. The optimal time and bandwidth factors are determined to maximize the throughput of secondary system under the performance constraint of primary system. The numerical results show that our proposed scheme significantly outperforms the non-cooperative scheme in terms of system throughput.

Reputation auction games for cooperative communications over green wireless networks

Realizing energy-efficient wireless communications is essential in facilitating the development of green next-generation wireless networks. Existing studies have shown that cooperative communications can significantly reduce total energy consumption within a network. Most of these studies assume that all nodes in the network transmit cooperatively. However, in practical networks, nodes may act selfishly and refuse to participate. Accordingly, this study proposes a novel reputation auction framework based on an indirect reciprocity concept to stimulate node cooperation in green wireless networks and to provide a means to adapt to changing network dynamics. The proposed framework comprises two sealed-bid auction schemes in which node reputations in single- and multiple-relay transmission scenarios, respectively, are allocated in an efficient and fair manner to generate energy savings from application of the indirect reciprocity model. An analytical model is proposed to evaluate the outage probability of the proposed schemes. The results derived using this model agree with those obtained from computer simulations. Also, an adaptive scheme is proposed to combine the advantages of single- and multiple-relay transmission. Simulations show that the proposed framework achieves higher energy efficiency and a lower outage probability than non-cooperative schemes. Furthermore, the adaptive scheme outperforms other schemes in terms of outage probability.

Distributed Polar Code Based on Plotkins Construction with MIMO Antennas in Frequency Selective Rayleigh Fading Channels

A Plotkin based polar coded orthogonal frequency division multiplexing (OFDM) with multiple input and multiple output (MIMO) antennas scheme is proposed and its performance over frequency selective Rayleigh fading channel has been evaluated. In the considered Plotkins construction, the longer length code word is formed on the basis of two shorter length code words. Due to the presence of a parallel split in the design of the considered Plotkins construction, the proposed scheme is efficiently extended to coded cooperative scenarios. As the relay always plays crucial role in the design of cooperative communication system, therefore an intelligent criteria for the selection of information bits is employed at the relay node. To check the efficacy and to maintain the complete fairness in the performance of the proposed coded cooperative scheme, the authors have also developed the traditional nested polar coded cooperative scheme in the context of OFDM with MIMO antennas. The Monte Carlo simulated bit error rate (BER) performance revealed that the proposed coded cooperative scheme outperforms the traditional nested polar coded cooperative OFDM with MIMO antennas scheme by gain of $$0.5 \;{\sim}\; 0.6$$ dBs. This significant gain in BER performance of the proposed coded cooperative scheme is made possible due to the efficient selection criteria and the joint successive cancellation (SC) decoding tecnique employed at relay node and at the destination node, respectively. Moreover, the proposed coded cooperative scheme outperforms its corresponding coded non-cooperative counterpart scheme by roughly a gain of 1 dB under identical conditions.

Broadcasting in dense linear networks: To cooperate or not to cooperate?

In this paper, the effectiveness of cooperative broadcast in high-density linear networks is studied. In the considered protocol, a single source sends messages continuously causing interference among messages and the goal is to reach to the entire network via cooperating relays. Sufficient conditions for successful broadcast are derived under two different transmission schemes: the unidirectional scheme and the bidirectional scheme. Our analysis shows that the broadcast behavior depends on the pathloss exponent γ and the type of transmission scheme even though the channel between two nodes are affected by small-scale fading. Unlike the noncooperative multihop broadcast, the cooperative broadcast propagates the message to the entire network successfully when γ ≤ 1 provided that network parameters satisfy certain conditions. Furthermore, for γ > 1, cooperative scheme becomes optimal under the bidirectional transmission when the information rate is below a threshold; however if the transmissions are unidirectional, noncooperative scheme becomes optimal. When compared with 2D networks, we demonstrate that the advantages of cooperative broadcast in linear networks are limited.

Outage performance of double-relay cooperative transmission network with energy harvesting

The double-relay cooperative user transmission network with energy harvesting is investigated and time switching-based double-relay cooperative transmission (TSDRCT) protocol is designed in this paper. In such a system, a source node transmits information to its destination node with the help of two energy harvesting cooperative nodes. The system outage probability is analyzed and an explicit expression for the outage probability is derived for decode-and-forward (DF) relay protocols, then simulation experiments are provided. The simulation results demonstrate the accuracy of the theoretical analysis, and also show that the proposed TSDRCT with energy harvesting relay is much better than traditional non-cooperative scheme in term of outage performance, and it does not increase system energy consumption.

Interference Coordination in Heterogeneous Small-Cell Networks: A Coalition Formation Game Approach

Heterogeneous small-cell networks have been identified as key technological components in accomplishing objectives of the fifth generation wireless communication system, in which the key point is the hyper dense deployment of small-cells. However, the interference among dense small-cells exacerbates in hyper dense deployment coupled with incessant use of multimedia services. In this paper, a network-side self-organized coalition formation approach for intra-tier interference mitigation primarily through neighborhood cooperation is proposed. By forming disjoint coalitions, small-cell access points (SAPs) are able to mitigate the interference within a coalition and thus improve their achievable data rates. The cooperative behavior among the neighborhood SAPs is formulated as a coalition formation game in partition form with non-transferable utility. Instead of fully reversible and irreversible methods used in prior studies, a merge and split based algorithm with partial reversibility rule which can obtain a final stable partition in the recursive core is proposed. The proposed algorithm converges to a final stable partition in a finite number of steps and works efficiently for both co-channel and orthogonal radio resource allocation modes. Simulation results have verified that the proposed algorithm can significantly improve the individual SAP throughput for both modes when compared with the conventional and the non-cooperative schemes.

Distributed polar-coded OFDM based on Plotkin’s construction for half duplex wireless communication

ABSTRACTA Plotkin-based polar-coded orthogonal frequency division multiplexing (P-PC-OFDM) scheme is proposed and its bit error rate (BER) performance over additive white gaussian noise (AWGN), frequency selective Rayleigh, Rician and Nakagami-m fading channels has been evaluated. The considered Plotkin’s construction possesses a parallel split in its structure, which motivated us to extend the proposed P-PC-OFDM scheme in a coded cooperative scenario. As the relay’s effective collaboration has always been pivotal in the design of cooperative communication therefore, an efficient selection criterion for choosing the information bits has been inculcated at the relay node. To assess the BER performance of the proposed cooperative scheme, we have also upgraded conventional polar-coded cooperative scheme in the context of OFDM as an appropriate bench marker. The Monte Carlo simulated results revealed that the proposed Plotkin-based polar-coded cooperative OFDM scheme convincingly outperforms the conventional polar-coded cooperative OFDM scheme by 0.5 ~ 0.6 dBs over AWGN channel. This prominent gain in BER performance is made possible due to the bit-selection criteria and the joint successive cancellation decoding adopted at the relay and the destination nodes, respectively. Furthermore, the proposed coded cooperative schemes outperform their corresponding non-cooperative schemes by a gain of 1 dB under an identical condition.

Radio Resource Management Scheme in NB-IoT Systems

Narrowband Internet of Things (NB-IoT) is the prominent technology that fits the requirements of future IoT networks. However, due to the limited spectrum (i.e., 180 kHz) availability for NB-IoT systems, one of the key issues is how to efficiently use these resources to support massive IoT devices? Furthermore, in NB-IoT, to reduce the computation complexity and to provide coverage extension, the concept of time offset and repetition has been introduced. Considering these new features, the existing resource management schemes are no longer applicable. Moreover, the allocation of frequency band for NB-IoT within LTE band, or as a standalone, might not be synchronous in all the cells, resulting in intercell interference (ICI) from the neighboring cells’ LTE users or NB-IoT users (synchronous case). In this paper, first a theoretical framework for the upper bound on the achievable data rate is formulated in the presence of control channel and repetition factor. From the conducted analysis, it is shown that the maximum achievable data rates are 89.2 Kbps and 92 Kbps for downlink and uplink, respectively. Second, we propose an interference aware resource allocation for NB-IoT by formulating the rate maximization problem considering the overhead of control channels, time offset, and repetition factor. Due to the complexity of finding the globally optimum solution of the formulated problem, a sub-optimal solution with an iterative algorithm based on cooperative approaches is proposed. The proposed algorithm is then evaluated to investigate the impact of repetition factor, time offset and ICI on the NB-IoT data rate, and energy consumption. Furthermore, a detailed comparison between the non-cooperative, cooperative, and optimal scheme (i.e., no repetition) is also presented. It is shown through the simulation results that the cooperative scheme provides up to 8% rate improvement and 17% energy reduction as compared with the non-cooperative scheme.

A game theoretic model and a distributed admission control scheme for quality of service routing

In this paper, we present an innovative distributed quality of service routing scheme suitable to operate in networks of general topology implementing a Diff-Serv service model for QoS support. The proposed scheme is based on a game theoretic non-cooperative model which exploits, on the one hand, the topological information distributed within the network by the current (non-QoS) link-state and distance-vector routing protocols and, on the other hand, the QoS information locally available at the node where the forwarding process takes place. In order to guarantee the satisfaction of a stability condition at each node, a distributed admission control (DAC) scheme is proposed to jointly operate with the non-cooperative routing scheme. The DAC decides if a new flow can be accepted without violating the nodes' stability constraints and provides each node with cumulative information about the status of the network downstream from its outgoing links.

Energy Beamforming Design and User Cooperation for Wireless Powered Communication Networks

We investigate user cooperation (UC) for wireless powered communication networks, where two single-antenna users are first wirelessly powered by a multi-antenna hybrid access point (H-AP), and then cooperatively transmit information signals to this H-AP via the harvested energy. To incorporate user fairness in the system performance, we formulate the weighted sum-rate maximization problem for both users to jointly optimize the energy beamforming vector, time allocation, and power allocation. Due to the non-convexity of this problem, we propose two UC schemes by employing a series of efficient variable substitutions and semidefinite programming relaxation to solve this problem. In addition, we show that the solution of the proposed schemes can achieve the global optimum by exploiting the rank-one characteristic of the energy beamforming matrix. Finally, numerical results are provided to validate our proposed schemes, which quantifies the impact of UC schemes by comparing them with the non-cooperative scheme.

Inter-Operator Resource Management for Millimeter Wave Multi-Hop Backhaul Networks

In this paper, a novel framework is proposed for optimizing the operation and performance of a large-scale multi-hop millimeter wave (mmW) backhaul within a wireless small cell network having multiple mobile network operators (MNOs). The proposed framework enables the small base stations to jointly decide on forming the multi-hop, mmW links over backhaul infrastructure that belongs to multiple, independent MNOs, while properly allocating resources across those links. In this regard, the problem is addressed using a novel framework based on matching theory composed of two, highly inter-related stages: a multi-hop network formation stage and a resource management stage. One unique feature of this framework is that it jointly accounts for both wireless channel characteristics and economic factors during both network formation and resource management. The multi-hop network formation stage is formulated as a one-to-many matching game, which is solved using a novel algorithm, that builds on the so-called deferred acceptance algorithm and is shown to yield a stable and Pareto optimal multi-hop mmW backhaul network. Then, a one-to-many matching game is formulated to enable proper resource allocation across the formed multi-hop network. This game is then shown to exhibit peer effects and, as such, a novel algorithm is developed to find a stable and optimal resource management solution that can properly cope with these peer effects. Simulation results show that, with manageable complexity, the proposed framework yields substantial gains, in terms of the average sum rate, reaching up to 27% and 54%, respectively, compared with a non-cooperative scheme in which inter-operator sharing is not allowed and a random allocation approach. The results also show that our framework improves the statistics of the backhaul sum rate and provides insights on how to manage pricing and the cost of the cooperative mmW backhaul network for the MNOs.