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Two fundamental problems related to multi-carrier modulation are considered in this paper. The first is finding the best modulation schemes in all subcarriers to minimize the total energy consumption required to send a given number of bits between two wireless nodes. The second is finding the best modulation schemes to maximize the number of bits transmitted between two nodes under total energy constraint...
This paper considers a three-terminal communication problem with one source node which broadcasts a common message to two destination nodes over a wireless medium. The destination nodes can cooperate over bidirectional wireless links. We study the minimum energy per information bit for this setup when there is no constraint on the available bandwidth. The physical link between any pair of nodes is...
Multiuser diversity (MUD) underlies much of the recent work on both, unicast and multicast scheduling design in wireless networks. In that context, a large channel variation among users is not a drawback. In the case of unicast, the user with the best quality channel can access the medium while the other users can wait for a better quality channel. In the case of multicast, the sender transmitting...
Recently, various space-time block coding (STBC) schemes have been developed to take advantage of the MIMO communication channel. The code designs using the pair-wise error probability of the maximum likelihood (ML) detector are based mainly on the rank and the determinant criteria. In particular, the current STBC designs focus on full diversity and the non-vanishing determinant, since such codes...
A communication network with a fixed number of sub-channels and several transmitter-receiver pairs under unit power constraint is considered. The achievable throughput of this network in the case of decentralized single-hop and one-shot game is investigated. It is assumed the number of links, N, as well as the number of sub-channels, M, are the common information among users. Moreover, direct channel...
The work presents a new approach to the concurrent optimization and design of transmitting and receiving parts of the adaptive communication systems (ACS). There is shown that optimal ACS used in the threshold mode provide, under given BER, a bit rate equal to the capacity of the forward channel.
A major problem in wireless networks is coping with limited resources, such as bandwidth and energy. These issues become a major algorithmic challenge in view of the dynamic nature of the wireless domain. We consider in this paper the single-transmitter power assignment problem under time-varying channels, with the objective of maximizing the data throughput. It is assumed that the transmitter has...
We introduce a new channel, which consists of an interference channel (IC) in parallel with an interference relay channel (IRC), to analyze the interaction between two selfish and cognitive transmitters who compete for a relay implementing the amplify-and-forward protocol. It is shown that whatever the relay location there is always an equilibrium in the resource allocation game where the users selfishly...
We consider the problem of a transmitter transmitting to its receiver over a wireless link subject to jamming and develop two online power control algorithms for maximizing wireless link quality (transmission rate). We assume that the transmitter transmits and the jammer interferes over a period of M time slots. The impact of the jammer is to deteriorate the quality of the wireless channel during...
In wireless communications, efficient power and interference control is critical to provide high-quality service. In this paper, we consider a downlink multi-user MIMO (multiple-input multiple-output) assuming that a transmitter has a peak power constraint and DTC (dirty tape coding) is implemented. A DTC scheme is used for cancelling interference. At each antenna of the transmitter, a summed signal...
Ultra wide-band (UWB) indoor channel is highly time scattered with large number of multi-path and a transmit power of UWB systems is limited to low level. One method to overcome these weak points of UWB communication is diversity combining technique. In this paper, we simulate and analyze performance of pulse position modulation-time hopping (PPM-TH) UWB systems adopting a space time block coding...
Growing interest in the wireless-enabled intelligent grid has prompted spectrum regulators to re-allocate various bands between 200 MHz and 2 GHz to fixed wireless applications. Although it is well-known that fixed wireless channels are subject to fading due to the motion of scatterers in the environment, most past efforts to characterize such fading on non-line-of-sight links in suburban macrocell...
In this work, we propose an enhancement to the DPC/ALP (distributed power control with active link protection) algorithm that allows fast power ramp-up without compromising the ALP guarantee. The original DPC algorithm was first augmented with ALP to provide absolute performance guarantees. The basis of active link protection lies on constraining the rate of the new links' transmission power increase...
In this paper, downlink opportunistic scheduling is studied in a multiuser environment with single-antenna base station and users. Analytical symbol error rate (SER) expressions are derived under the assumptions of full and quantized channel state information (CSI) at the transmitter. These expressions are used to optimize the channel state feedback parameters.
In this paper, the achievable rate of a K-user interference channel with single antenna at individual node is studied. Interference alignment and zero forcing are applied at the transmitter and receiver, respectively. It is well known from the paper [1] of Cadambe and Jafar that a multiplexing gain (degrees of freedom) of K/2 is achievable. We propose two new pre-coding methods and study how they...
The Geometric Mean Decomposition (GMD) for MIMO channel matrix can obtain identical subbchannel gains, which is a useful property to improve performance gains of precoding. In this paper, we combine the vector precoding with GMD for channel matrix to design the transceiver for MIMO transmission system. Under the proposed transceiver structure, the minimum square error (MSE) of receive symbols are...
The single antenna user nodes at the transmitters and at the receivers share their antennas to form a virtual multiple antenna system and to realize the cooperative diversity. It can enlarge the systempsilas capacity and enhance the service quality of the ad hoc network and improve the systempsilas performance. Applying the orthogonal property of the space-time coding, we transform the vector signal...
This paper deals with the chip-level equalization technique for large area synchronized-code division multiple access (LAS CDMA) system communications. In the downlink of LAS CDMA, frequency-selective multi-path channel often destroys the orthogonality of spread codes at receivers between users and introduces inter-path interference (IPI), inter-symbol interference (ISI) and multi-path access interference...
We consider opportunistic spectrum access (OSA) strategies for a transmitter in a multichannel wireless system, where a channel may or may not be available and the transmitter must sense/probe the channel to find out before transmission. Applications for this work include joint probing and transmission for a secondary user in a cognitive radio network. Limited by resources, e.g., energy and time,...
In this work, we consider the multiple access channel without channel side information at the transmitters, which have received considerable attention these last years. We propose a family of short distributed structured space-time codes achieving the diversity-multiplexing gain tradeoff (L. Zheng and D. Tse), (D.N. Tse,et.al) of this channel. We show that the designed codes outperform orthogonal...
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