A. S. Madhukumar

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The downlink power allocation in a two-tier cellular network which consists of a macrocell network underlaid by multiple femtocell networks is addressed in this paper. The paper aims to maximize the transmission capacity of the femtocell networks while guaranteeing that the interference experienced at the macro base station does not exceed an interference(More)
In this paper, a uniform matrix representation for Ultra-Wideband (UWB) Multiple-Input Multiple-Output (MIMO) systems with Time-Hopping Spread Spectrum (THSS) and Direct-Sequence Spread Spectrum (DSSS) methods is formulated. The Inter Symbol Interference (ISI) is considered for high data rate UWB transmissions in the presence of dense multipath in an indoor(More)
In this paper, a symbol relocated (SR) scheme has been proposed for variable spreading factor orthogonal frequency code division multiplexing (VSF-OFCDM) systems to achieve frequency diversity during retransmission. The performance has been evaluated for two combining schemes of hybrid auto repeat request (ARQ) namely chase combining and incremental(More)
This paper describes a combined modulation scheme for time hopping ultra wideband (TH-UWB) radio systems based on orthogonal pulse position modulation (OPPM) and bi-orthogonal pulse shape modulation (BPSM). A set of M=2<sup>k</sup> symbols are constructed by using L = 2<sup>l</sup> orthogonal pulse positions and N = 2<sup>k-l-1</sup> biorthogonal pulses,(More)
Wireless small cell networks and device-to-device (D2D) communications are seen as two major features of next-generation wireless networks. In this paper, a novel approach for enabling D2D communication underlaid on a wireless small cell network is proposed. Unlike existing works which focus on network performance analysis given a chosen communication mode,(More)