Adaptive minimum bit-error rate beamforming
An adaptive beamforming technique is proposed based on directly minimizing the bit-error rate (BER). It is demonstrated that this minimum BER (MBER) approach utilizes the antenna array elements more intelligently than the standard minimum mean square ...
Capacity regions and optimal power allocation for groupwise multiuser detection
In this letter, optimal power allocation and capacity regions are derived for groupwise successive interference cancellation (GSIC) systems operating in multipath fading channels, under imperfect channel estimation conditions. It is shown that the ...
On the complexity reduction of turbo decoding for wideband CDMA
Two simple but effective methods for reducing the average complexity (and power consumption) of the conventional turbo-cyclic-redundancy-check decoding scheme with negligible performance degradation in a wideband direct-sequence code-division multiple-...
Subspace approach to blind and semi-blind channel estimation for space-time block codes
A new approach to blind and semi-blind channel estimation for space-time block codes (STBCs) is presented. By exploiting the recently proposed generalized space-time block code framework, an STBC system is reduced from multiple-input multiple-output to ...
A full-rate, full-diversity four-antenna quasi-orthogonal space-time block code
We present a complex, full-rate quasi-orthogonal space-time block code for four transmit antennas. Using carefully tailored constellation phase rotations, we show that this code achieves full diversity for specialized PSK-based constellations. The ...
A time-frequency decision-feedback loop for carrier frequency offset tracking in OFDM systems
Acquisition and tracking are two crucial stages necessary to the carrier frequency synchronization in orthogonal frequency division multiplexing (OFDM) systems. In this letter, by employing the rotation property of OFDM data subcarriers, a simple time-...
Equal gain combining over Nakagami-n (rice) and Nakagami-q (Hoyt) generalized fading channels
Motivated by the importance of Nakagami-n (Rice) and Nakagami-q (Hoyt) statistical models to describe channel fading in land, mobile, terrestrial, and satellite telecommunications, we present an alternative moments-based approach to the performance ...
A simple approach to error probability with binary signaling over generalized fading channels with maximal ratio combining and noisy channel estimates
In this letter, we study the performance of binary signaling on generalized fading channels with maximal ratio combining (MRC) and imperfect channel estimates. With the assumption of the channel estimate being corrupted by a complex Gaussian random ...
Influence of fading on the Gaussian approximation for BPSK and QPSK with asynchronous cochannel interference
We investigate the performance of BPSK and QPSK with coherent detection and matched filtering in the presence of both time and phase asynchronous cochannel interfering signals. More precisely, we analyze the role played by different channel statistics ...
Detection performance of chaotic spreading LPI waveforms
Low probability of intercept (LPI) performance of a direct-sequence (DS) spread-spectrum (SS) system with chaotic spreading sequences is investigated in this paper. Several intercept receivers, including energy detectors, synchronous and asynchronous, ...
Blind equalization of turbo trellis-coded partial-response continuous-phase modulation signaling over narrow-band Rician fading channels
In this paper, a blind maximum-likelihood channel estimation algorithm is developed for turbo trellis-coded/continuous-phase modulation (TTC/CPM) signals propagating through additive white Gaussian noise (AWGN) and Rician fading environments. We present ...
Performance analysis of linear precoding based on field trials results of MIMO-OFDM system
We use field trial results obtained from a multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) wireless system with two transmitter and three receiver antennas (2×3), to first validate the properties of the ...
Predictive downlink beamforming for wideband CDMA over Rayleigh-fading channels
A new approach to adaptive downlink beamforming to combat fast Rayleigh fading is presented. In this approach, the antennas at the base transceiver station form transmit beam patterns according to the prediction of downlink channels. The channel ...
Accurate bit-error rate evaluation for synchronous MC-CDMA over Nakagami-m-fading channels using moment generating functions
In the bit-error rate (BER) analysis of code-division multiple-access (CDMA) systems, a Gaussian approximation is widely used to tackle the multiple access interference (MAI), although it does not always offer satisfactory accuracy. This paper ...
Group-blind intersymbol multiuser detection for downlink CDMA with multipath
Group-blind multiuser detectors for uplink code-division multiple-access (CDMA) were recently developed by Wang and Host-Madsen. These detectors make use of the spreading sequences of known users to construct a group constraint to suppress the intracell ...
Asymptotic behavior of the pairwise error probability with applications to transmit beamforming and rake receivers
We derive the precise asymptote of the pairwise error probability for high signal-to-noise ratio (SNR) and apply it to obtain new results concerning transmit beamforming and selective Rake receivers. For downlink beamforming (with N transmit antennas ...
Optimal training for MIMO frequency-selective fading channels
High data rates give rise to frequency-selective propagation effects. Space-time multiplexing and/or coding offer attractive means of combating fading and boosting capacity of multi-antenna communications. As the number of antennas increases, channel ...
On the uplink SIR of a mobile in soft handoff with applications to BLER estimation
We focus on the uplink and derive the joint probability density function of the signal to interference (+noise) ratios (SIRs) at the base stations (BSs) for the general case of n BSs supporting a mobile in soft handoff, each using maximal ratio ...
Measurement-based band allocation in multiband CDMA
Multiband code division multiple access (sometimes called multicarrier CDMA) is a promising approach to increasing the capacity of CDMA networks, while maintaining compatibility with existing systems. This paper investigates a family of algorithms for ...
Approximate performance analysis of heavily loaded slotted downlink channel in a wireless CDMA system supporting integrated voice/data services
This paper is concerned with the performance analysis of a slotted downlink channel in a wireless code division multiple access (CDMA) communication system with integrated packet voice/data transmission. The system model consists of a base station (BS) ...
Optimizing the ARQ performance in downlink packet data systems with scheduling
Third generation wireless systems typically employ adaptive coding and modulation, scheduling, and Hybrid Automatic Repeat reQuest (HARQ) techniques to provide high-speed packet data service on the downlink. Two main considerations in designing such a ...
A linear front end for iterative soft interference cancellation and decoding in coded CDMA
In this paper, after a description of the principles of iterative (turbo) multiuser detection for CDMA systems, a new structure, based on a linear user separator, is introduced and analyzed. The new user separator processes the matched filter outputs ...
Estimators of the Nakagami-m parameter and performance analysis
The Nakagami-m parameter is known to capture the envelope distribution of various fading channel conditions in wireless communications. The value of m is indicative of the severity of fading, and is a measure of channel quality, making its estimation ...
An integrated CDMA code assignment model for voice and data traffic in wireless communications
Wireless personal communication requires a provision of integrated services of multimedia traffic, such as voice and data, over the radio link. The multiple access protocols of code-division multiple-access (CDMA) techniques have been widely ...
Space-time turbo multiuser detection for coded MC-CDMA
The system capacity and performance of multicarrier code-division multiple-access (MC-CDMA) communication systems can be significantly enhanced by jointly employing MAP-based multiuser detection (MUD) and channel decoding techniques. In this paper, a ...
Receiver designs for Alamouti coded OFDM systems in fast fading channels
In this paper, receiver designs for orthogonal frequency-division multiplexing (OFDM) systems that exploit the Alamouti transmit diversity technique are addressed. In Alamouti space-time coded OFDM systems, the simple Alamouti decoding at the receiver ...
Nonline-of-sight error mitigation in mobile location
The location of mobile terminals has received considerable attention in the recent years. The performance of mobile location systems is limited by errors primarily caused by nonline-of-sight (NLOS) propagation conditions. We investigate the NLOS error ...
Reduced complexity receivers for layered space-time CPM
Layered space-time (LST) transmissions employing continuous phase modulations (CPM) are well motivated for both bandwidth- and power-limited multiantenna communications. However, one of the major challenges for LST-CPM is the high complexity it incurs ...
A dynamic multiple-threshold bandwidth reservation (DMTBR) scheme for QoS provisioning in multimedia wireless networks
Next-generation wireless networks target to provide quality of service (QoS) for multimedia applications. We study the wireless systems that support two QoS requirements: keeping the handoff dropping probability less than a predefined QoS threshold ...
MMSE and adaptive prediction of time-varying channels for OFDM systems
We propose decision-directed channel predictors for orthogonal frequency-division multiplexing (OFDM) communications over time-varying channels. Channel prediction is capable of yielding up-to-date channel state information even without regular ...
