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Device-to-Device (D2D) communication underlying 5G cellular networks enable using direct communication between devices as a relay strategy for coverage extension. We consider such a D2D-relaying approach in a scenario where there are multiple candidate devices to be selected as relays. Both backhaul and D2D transmissions are performed in uplink cellular resources, and are subject to cellular uplink...
We consider full-duplex multi-hop forwarding in a Beyond 4G local area network. In the network, there is a high density of self-backhauling relay nodes that simultaneously act as access points towards the users, in addition to few nodes with wired backhaul. The access is framed and synchronized along the multi-hop flow, and the nodes apply time division duplexing. Interference cancelation as well...
We calculate the optimal muting ratio for time domain Enhanced Inter-Cell Interference Coordination (TDM eICIC) in a downlink HetNet scenario, consisting of macrocell and femtocell users. First we derive analytically the optimal muting ratio in a simplified scenario, and identify a particular case where all macro users are either strongly or not at all affected by the presence of femtocells. In this...
We study a distributed approach for Primary Component Carrier (PCC) selection to manage interference and to improve cell edge performance in a heterogeneous network. To avoid cell outage caused by PCC selection based on path loss between neighboring base stations (BSs), we argue that carrier reselection based on handover measurements performed by the User Equipments (UEs) is necessary. We propose...
Local area deployments in general and femtocells in particular have proved to be an effective solution for providing ubiquitous coverage in a cost-efficient manner, satisfying the high data rate and QoS requirements for LTE-Advanced systems. In this paper, we investigate inter-cell interference management schemes for dense local area deployments. We propose a distributed capacity based channel allocation...
Modern cellular communication systems are based on frequency reuse 1. Although reuse 1 promises high peak data rates and significantly simplified network planning, the cell edge or cell overlap areas suffer from excessive inter-cell interference. In this work we address interference management for downlink part of these systems. Part of the radio resources is primarily reserved for protected access...
In LTE-Advanced, multiuser MIMO has been identified as a key technique for increasing system spectral efficiency in closed-loop MIMO. Transmission parameters like precoding and transmission rate are adapted based on finite rate feedback from the users. Switching between single user and multiuser transmission modes is possible without higher layer signaling, which means that the feedback should be...
We investigate the impact of dynamic offset (the relative timing difference) between the frames of a Time Division Duplex (TDD) system on system utility and expected throughput. We use computer simulation to maximize three utility functions through exhaustive search over different frame offset alternatives. We initially carry out investigation in a small three-cell system and then finally we investigate...
We consider Device-to-Device (D2D) communication underlaying cellular networks to improve local services. The system aims to optimize the throughput over the shared resources while fulfilling prioritized cellular service constraints. Optimum resource allocation and power control between the cellular and D2D connections that share the same resources are analyzed for different resource sharing modes...
We study the rate adaptation of a combined system with Adaptive Modulation and Coding (AMC) and Hybrid ARQ (HARQ) in the presence of Channel Quality Indicator (CQI) errors. An average BLock Error Rate (BLER) is imposed to maintain a target error rate. We formulate a generic average throughput expression that accommodates the possible CQI errors. The generic expression is adapted to different forms...
In this paper we consider the CQI reporting problem in MIMO downlink with adaptive switching between single user and multiuser mode and finite rate feedback. The feedback consist of channel directional information, which is the precoding weight, and channel quality information, which is a quantized value of estimated post processing SINR. The quantization of the channel directional information causes...
In this paper, we consider optimum rate quantization of Adaptive Modulation and Coding (AMC) systems by jointly designing the MCS levels and intervals. Optimum quantization leads to coupled non-algebraic equations, and is generally not amenable for analysis. Here, we propose two approximate AMC rate quantization methods, which are based on an observation of the optimal condition and the numerical...
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