Uplink Of Heterogeneous Networks Research Articles

Joint User Association and Resource Allocation in the Uplink of Heterogeneous Networks

This letter considers the problem of joint user association (UA), sub-channel assignment, antenna selection (AS), and power control in the uplink (UL) of a heterogeneous network such that the data rate of small cell users can be maximized while the macro-cell users are protected by imposing a threshold on the cross-tier interference. The considered problem is a non-convex mixed integer non-linear programming (MINLP). To tackle the problem, we decompose the original problem into two sub-problems: (i) joint UA, sub-channel assignment, and AS, and (ii) power control. Then, we iteratively solve the subproblems by applying the tools from majorization-minimization (MM) theory and augmented Lagrange method, respectively, and obtain locally optimal solutions for each sub-problem. Simulation results illustrate that our proposed scheme outperforms existing schemes. Complexity analysis of the proposed algorithm is also presented.

A QoE-Oriented Network Selection Mechanism in Heterogeneous Wireless Networks

In order to guarantee the UAV video uplink in heterogeneous networks, a novel access network selection mechanism was proposed in this paper. Due to the unknown Channel State Information(CSI), the issue was first modeled as the Multi-Armed Bandit (MAB) problem. Then, the reward function was built and the Quality of Experience (QoE) of video was considered. By means of three typical solving algorithms, decisions could be made between utilization and exploration. The simulation results show that the mechanism can effectively solve the network selection problem of video transmission in heterogeneous networks.

Joint signal alignment precoding and physical network coding for heterogeneous networks

Mobile traffic in cellular based networks is increasing exponentially, mainly due to the use of data intensive services like video. One effective way to cope with these demands is to reduce the cell-size by deploying small-cells along the coverage area of the current macro-cell system. The deployment of small-cells significantly improves the indoor coverage. Nevertheless, as additional spectrum licenses are difficult and expensive to acquire, it is expected that the macro and small-cells will coexist under the same spectrum. The coexistence of the two systems results in cross-tier/inter-system interference. In this context, we consider the application of joint signal alignment (SA) and physical network coding (PNC) for the uplink of heterogeneous networks, in order to cancel the interference generated from small-cells at the macro-cell user terminal. The joint design of SA and PNC allows to serve more users than the case where only PNC or interference alignment (IA) is employed individually. We compare our proposed joint SA-PNC schemes with the recently designed IA based techniques for the uplink heterogeneous systems. Simulation results show that the proposed SA-PNC is quite efficient to remove the inter-tier/system interference while allowing to increase the overall data rate, by serving more users, as compared with the IA based methods

Power-efficient distributed resource allocation under goodput QoS constraints for heterogeneous networks

This work proposes a distributed resource allocation (RA) algorithm for packet bit-interleaved coded OFDM transmissions in the uplink of heterogeneous networks (HetNets), characterized by small cells deployed over a macrocell area and sharing the same band. Every user allocates its transmission resources, i.e., bits per active subcarrier, coding rate, and power per subcarrier, to minimize the power consumption while both guaranteeing a target quality of service (QoS) and accounting for the interference inflicted by other users transmitting over the same band. The QoS consists of the number of information bits delivered in error-free packets per unit of time, or goodput (GP), estimated at the transmitter by resorting to an efficient effective SNR mapping technique. First, the RA problem is solved in the point-to-point case, thus deriving an approximate yet accurate closed-form expression for the power allocation (PA). Then, the interference-limited HetNet case is examined, where the RA problem is described as a non-cooperative game, providing a solution in terms of generalized Nash equilibrium. Thanks to the closed-form of the PA, the solution analysis is based on the best response concept. Hence, sufficient conditions for existence and uniqueness of the solution are analytically derived, along with a distributed algorithm capable of reaching the game equilibrium.