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OFDMA has emerged as a promising physical layer technology for LTE wireless networks. OFDM solves the problem of co-channel interference in intra-cell to some extent because of the orthogonality of subcarriers, along with the character of guard interval and cyclic prefix. However, inter-cell interference still exists, especially the cell edge users suffer from interferences seriously, which leads...
Femtocells can offload the traffic of macrocells and satisfy the big high-data-rate wireless communication requirement of indoor users. Due to the large number of fmetocells deployed by users, a significant challenge this new access technology brings to us is coordinating the cross-tier interference. Much special attention has been paid to solve the problem. This paper presents a novel strategy to...
The concept of small cells such as femtocell has been regarded as a promising solution to achieve green communication and deal with the coverage hole and growth of traffic within macrocells. However, the unpredictable deployment pattern of such nodes makes static network planing impractical and the overlaying macrocell and femtocell tiers may suffer significant cross-tier interference from each other...
Distributed uplink power allocation technique as a strategy for maintaining the quality of service (QoS) is described for orthogonal frequency division multiplexing (OFDM) based networks. In proposed algorithm, the power is allocated to subcarriers having large signal-to-interference-plus-noise ratio (SINR) according to the criterion. In order to reduce cochannel interference, we propose the power...
To improve power efficiency in vehicle-to-roadside infrastructure (V2I) communication networks, this paper proposes a joint power and sub-carrier assignment policy under delay aware quality of service (QoS) requirements. Due to the real-time nature of the V2I transmissions, the proposed policy should satisfy delay aware QoS requirements with a minimized power consumption. In particular, we develop...
LTE (Long Term Evolution) supports QoS (Quality of Service) with several service classes. For each class of traffic, a big difference exists on BER (Bit Error Rate) requirement. This leads to a considerable difference in transmission power for various classes of traffic. In this paper, a novel scheduler is designed and proposed for LTE which supports CoS (Class of Service) with the consideration of...
We study in this paper the resource allocation matter for unlicensed multiband ultra-wideband (UWB) users in the context of high-rate wireless personal area network (WPAN). The problem is viewed as a coexistence problem with existing licensed systems. The QoS support and the interference mitigation are jointly considered in this study to derive a novel interference power control mechanism that differentiates...
The femtocells are very promising concept for wireless networks to significantly enhance system capacity. Nevertheless, a lot of challenges must be still addressed. The paper focuses on a power control mechanism and proposes a novel approach for dynamic adaptation of transmitting power of femtocell access points. The basic idea is to adapt the transmitting power of femtocells according to current...
This paper proposes a novel channel allocation method for multi-cells OFDMA-FDD networks with a reused frequency factor (RFF) of one. The proposed algorithm predicts the co-channel interference (CCI) of active mobile stations (MSs) before allocating suitable subcarriers to a new MS. In order to maintain a desired quality of service (QoS) of the network, only subcarriers having signal-to-interference-plus-noise...
4G cellular systems and the IMT Advanced candidates will provide broadband wireless access with QoS. Especially in multihop configurations of these systems the base station controls resources centrally while relays can take over a part of the responsibility on the second hop. To make this work on layer two, scheduling is the most important task. However, many dimensions of the problem lead to much...
Modern wireless multiuser multicarrier systems (MU-MC) incorporate Dynamic Resource Allocation (DRA), Adaptive Modulation and Coding (AMC) and Power Control (PC) to exploit multiuser diversity and achieve higher system throughput. In the literature, only a few proposed algorithms deal with the contiguous DRA problem (contiguous collection of resources). This paper formulates this high complexity problem,...
In this paper, an energy efficient adaptive modulation scheme is proposed for a wireless cognitive radio ad hoc network, where each node is equipped with cognitive radio and the network is an OFDMA system operating on time slots. In each slot, the users with new traffic demand will sense the spectrum and locate the available subcarrier set. Then they choose subcarriers with favorable channel condition...
This paper explores the attributes, layering models and objective functions in cross layer designs for mobile ad hoc wireless networks by taking all the statistical characteristics and constraints from the physical (PHY) layer, media access control (MAC) layer and network (NET) layer into consideration. This paper reviews the entire network optimization across all the PHY/MAC/NET layers. At the PHY...
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