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One of the main challenges of communication in the absence of transmitter channel knowledge is codebook universality, i.e., the existence of a single codebook that guarantees a given rate for all channel states. We address this problem for a class of ergodic fading multiple-input multiple-output (MIMO) channels, whose fading distribution is not necessarily isotropic. It is shown that a universal codebook...
The performance of lattice coding and decoding for the ergodic fading point-to-point channel is studied in the presence of channel estimation errors at the receiver. We show that lattice codes achieve rates within a constant gap to that of Medard's scheme with Gaussian input. Interestingly, the gap does not depend on the channel estimation error variance nor the signal-to-noise ratio (SNR), for a...
This paper considers communication over the point-to-point Gaussian channel with stationary and ergodic channel gain and full channel state information. The capacity of this channel can be achieved in a straightforward manner via any capacity-achieving codebook for the non-fading Gaussian channel, in conjunction with separable coding, i.e., coding independently over each fading state. Despite its...
Many aspects of lattice coding and decoding under time-varying multiple-antenna systems remain unexplored. This paper studies the achievable rates using lattice codes for the multiple-input- multiple-output (MIMO) point-to-point channel with ergodic fading and channel state information at the receiver. The proposed lattice coding scheme involves the use of decision regions that are universal for almost...
A multiple-input-multiple-output (MIMO) version of Costa's dirty paper channel is studied, where both the input signal and the state experience ergodic fading with channel state information at the receiver. An inner bound using lattice coding and decoding is derived and its gap to the point-to- point ergodic capacity is computed. Under Rayleigh fading, the gap is a constant that vanishes as the number...
A modified version of Costa's dirty paper channel is studied, in which both the input signal and the state experience stationary and ergodic time-varying fading. The fading coefficients are assumed to be known exclusively at the receiver. An inner bound of the achievable rates using lattice codes is derived and compared to an outer bound of the capacity. For a wide range of fading distributions, the...
The performance of lattice codes in the additive white Gaussian noise (AWGN) channel has attracted much attention lately, however, their performance under ergodic fading channels has been relatively unexplored. We show that lattice coding and decoding achieve the capacity of the ergodic point-to-point and multiple-access channels (MAC). Additionally, a low-complexity scheme is proposed for the ergodic...
It is known that lattice coding can achieve the capacity of the additive white Gaussian noise (AWGN) channel. This paper addresses the performance of lattice codes in the ergodic fading channel. Using nested lattice codes and ambiguity decoding, we show that the rates achieved by lattice coding and decoding are within a constant gap of the capacity of the ergodic channel at moderate and high signal-to-noise-ratio...
A novel transmission scheme is developed for the downlink frame of cellular networks. Each base station (BS) aims at iteratively balancing the throughput at the mobile stations (MSs) of its cell with the interference it causes at the MSs of the neighboring cells, requiring negligible coordination between the BSs. A simplified version of the scheme that neither requires iterations nor cooperation is...
A transmission scheme is developed for the downlink frame of cellular networks. While the mobile stations (MSs) maximize the signal power from the serving base station (BS), each BS aims at balancing the signal power of its users with the interference caused at the MSs of the neighboring cells, based on an approximated performance metric. A closed form solution for the beamforming vectors of the BSs...
The downlink frame of a cellular relay network is considered, where a shared MIMO decode-and-froward relaying is used to serve the users at the edge of the cell. The relay employs zero-forcing beamforming to manage the interference among the mobile stations (MSs) at the edge of the cell. A non-cooperative scheme is considered where there is no coordination between the base stations (BSs) and the relay...
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