Review on Radio Resource Allocation Optimization in LTE/LTE-Advanced using Game Theory

Recently, there has been a growing trend toward ap-plying game theory (GT) to various engineering fields in order to solve optimization problems with different competing entities/con-tributors/players. Researches in the fourth generation (4G) wireless network field also exploited this advanced theory to overcome long term evolution (LTE) challenges such as resource allocation, which is one of the most important research topics. In fact, an efficient de-sign of resource allocation schemes is the key to higher performance. However, the standard does not specify the optimization approach to execute the radio resource management and therefore it was left open for studies. This paper presents a survey of the existing game theory based solution for 4G-LTE radio resource allocation problem and its optimization

Cognition-inspired 5G cellular networks: a review and the road ahead

Despite the evolution of cellular networks, spectrum scarcity and the lack of intelligent and autonomous capabilities remain a cause for concern. These problems have resulted in low network capacity, high signaling overhead, inefficient data forwarding, and low scalability, which are expected to persist as the stumbling blocks to deploy, support and scale next-generation applications, including smart city and virtual reality. Fifth-generation (5G) cellular networking, along with its salient operational characteristics - including the cognitive and cooperative capabilities, network virtualization, and traffic offload - can address these limitations to cater to future scenarios characterized by highly heterogeneous, ultra-dense, and highly variable environments. Cognitive radio (CR) and cognition cycle (CC) are key enabling technologies for 5G. CR enables nodes to explore and use underutilized licensed channels; while CC has been embedded in CR nodes to learn new knowledge and adapt to network dynamics. CR and CC have brought advantages to a cognition-inspired 5G cellular network, including addressing the spectrum scarcity problem, promoting interoperation among heterogeneous entities, and providing intelligence and autonomous capabilities to support 5G core operations, such as smart beamforming. In this paper, we present the attributes of 5G and existing state of the art focusing on how CR and CC have been adopted in 5G to provide spectral efficiency, energy efficiency, improved quality of service and experience, and cost efficiency. This main contribution of this paper is to complement recent work by focusing on the networking aspect of CR and CC applied to 5G due to the urgent need to investigate, as well as to further enhance, CR and CC as core mechanisms to support 5G. This paper is aspired to establish a foundation and to spark new research interest in this topic. Open research opportunities and platform implementation are also presented to stimulate new research initiatives in this exciting area

A Submodular Optimization Framework for Outage-Aware Cell Association in Heterogeneous Cellular Networks

In cellular heterogeneous networks (HetNets), offloading users to small cell base stations (SBSs) leads to a degradation in signal to interference plus noise ratio (SINR) and results in high outage probabilities for offloaded users. In this paper, we propose a novel framework to solve the cell association problem with the intention of improving user outage performance while achieving load balancing across different tiers of BSs. We formulate a combinatorial utility maximization problem with weighted BS loads that achieves proportional fairness among users and also takes into account user outage performance. A formulation of the weighting parameters is proposed to discourage assigning users to BSs with high outage probabilities. In addition, we show that the combinatorial optimization problem can be reformulated as a monotone submodular maximization problem and it can be readily solved via a greedy algorithm with lazy evaluations. The obtained solution offers a constant performance guarantee to the cell association problem. Simulation results show that our proposed approach leads to over 30% reduction in outage probabilities for offloaded users and achieves load balancing across macrocell and small cell BSs

Cooperative retransmission protocols in fading channels : issues, solutions and applications

Future wireless systems are expected to extensively rely on cooperation between terminals, mimicking MIMO scenarios when terminal dimensions limit implementation of multiple antenna technology. On this line, cooperative retransmission protocols are considered as particularly promising technology due to their opportunistic and flexible exploitation of both spatial and time diversity. In this dissertation, some of the major issues that hinder the practical implementation of this technology are identified and pertaining solutions are proposed and analyzed. Potentials of cooperative and cooperative retransmission protocols for a practical implementation of dynamic spectrum access paradigm are also recognized and investigated. Detailed contributions follow. While conventionally regarded as energy efficient communications paradigms, both cooperative and retransmission concepts increase circuitry energy and may lead to energy overconsumption as in, e.g., sensor networks. In this context, advantages of cooperative retransmission protocols are reexamined in this dissertation and their limitation for short transmission ranges observed. An optimization effort is provided for extending an energy- efficient applicability of these protocols. Underlying assumption of altruistic relaying has always been a major stumbling block for implementation of cooperative technologies. In this dissertation, provision is made to alleviate this assumption and opportunistic mechanisms are designed that incentivize relaying via a spectrum leasing approach. Mechanisms are provided for both cooperative and cooperative retransmission protocols, obtaining a meaningful upsurge of spectral efficiency for all involved nodes (source-destination link and the relays). It is further recognized in this dissertation that the proposed relaying-incentivizing schemes have an additional and certainly not less important application, that is in dynamic spectrum access for property-rights cognitive-radio implementation. Provided solutions avoid commons-model cognitive-radio strict sensing requirements and regulatory and taxonomy issues of a property-rights model

Distributed radio resource allocation in wireless heterogeneous networks

This dissertation studies the problem of resource allocation in the radio access network of heterogeneous small-cell networks (HetSNets). A HetSNet is constructed by introducing smallcells(SCs) to a geographical area that is served by a well-structured macrocell network. These SCs reuse the frequency bands of the macro-network and operate in the interference-limited region. Thus, complex radio resource allocation schemes are required to manage interference and improve spectral efficiency. Both centralized and distributed approaches have been suggested by researchers to solve this problem. This dissertation follows the distributed approach under the self-organizing networks (SONs) paradigm. In particular, it develops game-theoretic and learning-theoretic modeling, analysis, and algorithms. Even though SONs may perform subpar to a centralized optimal controller, they are highly scalable and fault-tolerant. There are many facets to the problem of wireless resource allocation. They vary by the application, solution, methodology, and resource type. Therefore, this thesis restricts the treatment to four subproblems that were chosen due to their significant impact on network performance and suitability to our interests and expertise. Game theory and mechanism design are the main tools used since they provide a sufficiently rich environment to model the SON problem. Firstly, this thesis takes into consideration the problem of uplink orthogonal channel access in a dense cluster of SCs that is deployed in a macrocell service area. Two variations of this problem are modeled as noncooperative Bayesian games and the existence of pure-Bayesian Nash symmetric equilibria are demonstrated. Secondly, this thesis presents the generalized satisfaction equilibrium (GSE) for games in satisfaction-form. Each wireless agent has a constraint to satisfy and the GSE is a mixed-strategy profile from which no unsatisfied agent can unilaterally deviate to satisfaction. The objective of the GSE is to propose an alternative equilibrium that is designed specifically to model wireless users. The existence of the GSE, its computational complexity, and its performance compared to the Nash equilibrium are discussed. Thirdly, this thesis introduces verification mechanisms for dynamic self-organization of Wireless access networks. The main focus of verification mechanisms is to replace monetary transfers that are prevalent in current research. In the wireless environment particular private information of the wireless agents, such as block error rate and application class, can be verified at the access points. This verification capability can be used to threaten false reports with backhaul throttling. The agents then learn the truthful equilibrium over time by observing the rewards and punishments. Finally, the problem of admission control in the interfering-multiple access channel with rate constraints is addressed. In the incomplete information setting, with compact convex channel power gains, the resulting Bayesian game possesses at least one pureBayesian Nash equilibrium in on-off threshold strategies. The above-summarized results of this thesis demonstrate that the HetSNets are amenable to self-organization, albeit with adapted incentives and equilibria to fit the wireless environment. Further research problems to expand these results are identified at the end of this document

A Novel Approach for Centralized 3D Radio Resource Allocation and Scheduling in Dense HetNets for 5G Control-/User-plane Separation Architectures

This paper presents a centralized 3-dimensional radio resources (namely, time, frequency, and power) allocation and scheduling approach for control-plane and user-plane (C-/U-plane) separation architectures for fifth generation mobile networks. A central station is considered where schedulers of all base stations (BSs) are located. We consider a multi-tier network that comprises of a macrocell BS (MCBS), several outdoor picocell BSs, and a number of indoor femtocell BSs (FCBSs) deployed in a number of multi-storage buildings. The system bandwidth is reused in FCBSs within each building orthogonally. In contrast to the conventional almost blank subframe, we consider a fully blank subframe based time-domain enhanced intercell interference coordination to split completely C-/U-plane traffic such that the control-plane can be served only by the MCBS and the user-plane of user equipments by their respective BSs. We propose two power management schemes for FCBSs based on whether or not the coordinated multi-point communication with joint transmission (JT CoMP) is employed during off-state of a FCBS and develop a power control mechanism for both a single user and multi-user per FCBS scenarios. An optimal value of average activation factor (OAF) for a FCBS is derived to trade-off its serving capacity and transmit power saving factor. It is shown that in order to improve the network capacity, a FCBS needs to operate at an average activation factor (AAF) greater than its OAF using JT CoMP to serve neighboring on-state FCBSs during its normal off-state, whereas at an AAF less than the OAF to improve the energy efficiency. With a system level simulation, we show that the capacity of a FCBS increases, whereas its power saving factor decreases linearly with an increase in its AAF because of serving increased traffic, and an OAF of 0.5 for the capacity scaling factor and greater than 0.5 for are found.This paper presents a centralized 3-dimensional radio resources (namely, time, frequency, and power) allocation and scheduling approach for control-plane and user-plane (C-/U-plane) separation architectures for fifth generation mobile networks. A central station is considered where schedulers of all base stations (BSs) are located. We consider a multi-tier network that comprises of a macrocell BS (MCBS), several outdoor picocell BSs, and a number of indoor femtocell BSs (FCBSs) deployed in a number of multi-storage buildings. The system bandwidth is reused in FCBSs within each building orthogonally. In contrast to the conventional almost blank subframe, we consider a fully blank subframe based time-domain enhanced intercell interference coordination to split completely C-/U-plane traffic such that the control-plane can be served only by the MCBS and the user-plane of user equipments by their respective BSs. We propose two power management schemes for FCBSs based on whether or not the coordinated multi-point communication with joint transmission (JT CoMP) is employed during off-state of a FCBS and develop a power control mechanism for both a single user and multi-user per FCBS scenarios. An optimal value of average activation factor (OAF) for a FCBS is derived to trade-off its serving capacity and transmit power saving factor. It is shown that in order to improve the network capacity, a FCBS needs to operate at an average activation factor (AAF) greater than its OAF using JT CoMP to serve neighboring on-state FCBSs during its normal off-state, whereas at an AAF less than the OAF to improve the energy efficiency. With a system level simulation, we show that the capacity of a FCBS increases, whereas its power saving factor decreases linearly with an increase in its AAF because of serving increased traffic, and an OAF of 0.5 for the capacity scaling factor k = 1/2 and greater than 0.5 for k < 1 are found.&nbsp