Towards understanding energy requirements for computation with noisy elements, we consider the computation of an arbitrary k-input, k-output binary invertible function. In our model, not all gates need to be noisy. However, the input nodes on the computation graph must be separated from the output nodes by a noisy cut. For this setup, we show that for the “information-friction” model proposed r...

This paper addresses the performance of the downlink High Speed Data Packet Access (HSDPA) in QPSK mode. Transmit Diversity (TD) enhancement schemes such as Space Time Transmit Diversity (STTD) and Selective Transmit Diversity (STD), alongside a Power Control (PC) scheme, are covered to improve the system capacity. To evaluate the performance and the advantages of all the schemes under differen...

The information capacity of the mismatched stationary continuous-time Gaussian channel is determined. The assumptions placed on the signal process are less restrictive than those given in previous treatments. Moreover. Lhe assumptions used may have operational advantages over those used previously. *Department of Statistics. University of North Carolina. Chape] Hill. N.C. 27599-3260 *Department...

We determine the feedback capacity region of a two user Gaussian multiple access channel (MAC) with multiple antennas at the base station and a single antenna at each user. The vector MAC and broadcast channels (BC) with a single antenna at the base station and multiple antennas at each user are shown to be equivalent to scalar MACs and BCs, respectively. We also determine the capacity enhancem...

We provide a counterexample to Cover’s conjecture that the feedback capacity CFB of an additive Gaussian noise channel under power constraint P be no greater than the nonfeedback capacity C of the same channel under power constraint 2P , i.e., CFB(P ) C(2P ). Index Terms|Additive Gaussian noise channels, channel capacity, conjecture, counterexample, feedback.

In this paper, we revisit the problem of finding the average capacity of the Gaussian feedback channel. First, we consider the problem of finding the average capacity of the analog colored Gaussian noise channel where the noise has an arbitrary spectral density. We introduce a new approach to the problem where we solve the problem over a finite number of transmissions and then consider the limi...

Channel capacity is usually undetermined in cooperative communication because of the various power allocations. In order to improve the channel capacity, power allocation for tri-terminal cooperative communication is discussed for Gaussian channel gains in EGC model and MRC model. The optimum power allocation algorithm, viewing channel capacity as the destination function, is presented. The pap...

The capacity region of a two-user linear Gaussian compound Multiple Access Channel with common message (CMACC) and intersymbol interference (ISI) under an input power constraint is derived. To obtain the capacity region we first convert the channel to its equivalent memoryless one by defining an n-block memoryless circular Gaussian CMACC model. We then make use of the discrete Fourier transform...

Recent investigations have shown sum capacity results within a constant bit-gap for several channel models, e.g. the two-user Gaussian interference channel (G-IC), k-user G-IC or the Gaussian X-channel. This has motivated investigations of interferencelimited multi-user channels, for example, the Gaussian interfering multiple access channel (G-IMAC). Networks with interference usually require t...

The feedback capacity of the stationary Gaussian additive noise channel has been open, except for the case where the noise is white. Here we obtain the closed-form feedback capacity of the first-order moving average additive Gaussian noise channel. Specifically, the channel is given by Yi = Xi +Zi, i = 1, 2, . . . , where the input {Xi} satisfies a power constraint and the noise {Zi} is a first...