Performances of multiband orthogonal frequency division multiplexing (MB-OFDM) and direct sequence based ultra wideband (DS-UWB) systems are studied in interfered multipath channel. The radio channel is based on the modified Saleh-Valenzuela model. The studies related to the comparison between MB-OFDM and DS-UWB within interference seems to be unsubstantial in the literature. Therefore, it is c...

In this paper we determine the delivery time for a multi-server coded caching problem when the cache size of each user is small.We propose an achievable scheme based on coded cache content placement, and employ zero-forcing techniques at the content delivery phase. Surprisingly, in contrast to previous multi-server results which were proved to be order-optimal within a multiplicative factor of ...

This article introduces the notion of uncoded, partially overlapped, staggered quadrature raised-cosine modulation (SQORC-P) as well as that of a trellis-coded form that is implemented as a specific embodiment of the recently introduced crosscorrelated trellis-coded quadrature modulation (XTCQM). Consideration is given to the power spectral density (PSD) of the scheme over both linear and nonli...

Various space time code (STC) designs have been proposed to obtain full diversity at full rate in multiple-input multiple-output (MIMO) channels for uncoded systems. However, commercial wireless systems typically employ powerful channel codes such as turbo codes and low density parity check (LDPC) codes together with an STC. For these applications, an STC optimized for uncoded systems may not p...

Adaptive signaling schemes, which employ the current channel fading values to optimize the transmitted signal, have recently been presented for time-varying Rayleigh fading channels. These schemes have employed set-partitioned trellis-coded modulation (TCM) and have adapted the number of uncoded bits on a given symbol based on the corresponding channel estimate. However, the characterization of...

We consider wireless caches located in the plane according to general point process and specialize the results for the homogeneous Poisson process. A large data file is stored at the caches, which have limited storage capabilities. Hence, they can only store parts of the data. Clients can contact the caches to retrieve the data. We compare the expected cost of obtaining the complete data under ...

The benefits of receiver antenna diversity in a Universal Mobile Telecommunications System (UMTS) handset were studied. Two different channel models were used, one an extension to the 3GPP multipath fading channels and the other based on 3-D scattering and angular weighting via a practically realisable antenna configuration. Simulated performance benefits arising from the use of a second receiv...