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With the rapid growth of frequency-hopped (FH) wireless networks, interference due to frequency collisions has become one of the main performance-limiting challenges. This paper proposes a novel multiuser detection method for joint hop timing and frequency estimation, which is capable of unraveling and demodulating multiple FH transmissions in the presence of collisions and unknown hop patterns without retransmission. The method is based on the principle of dynamic programming (DP) coupled with two-dimensional harmonic retrieval (2-D HR) or low-rank trilinear decomposition, and it remains operational even with multiple unknown hop rates, frequency offsets, and asynchronism. The model is based on frequency-shift keying (FSK) and phase-shift keying (PSK) modulation, but the algorithms are also evaluated with Gaussian minimum-shift keying (GMSK) modulation and shown to be robust. [ABSTRACT FROM PUBLISHER]

This article reviewed the various aspects of MAC-PHY cross-layer designs, with the goals of introducing pertinent queuing and stability analysis tools to the SP-oriented readership, and illustrating the advantages of such cross-layer designs using the recently introduced class of xNDMA protocols as an example. The results of queuing analysis show that a jointly designed MAC-PHY layer provides increased throughput and low delay characteristics over a wide range of offered loads. The throughput-delay benefits of xNDMA come at the expense of a moderate increase in receiver complexity and power consumption. [ABSTRACT FROM PUBLISHER]

Fair queueing (FQ) algorithms, which have been proposed for quality of service (QoS) wireline/wireless networking, rely on the fundamental idea that the service rate allocated to each user is proportional to a positive weight. Targeting wireless data networks with a multicode CDMA-based physical layer, we develop FQ with time-varying weight assignment in order to minimize the queueing delays of mobile users. Applying dynamic programming, we design a computationally efficient algorithm which produces the optimal service rates while obeying 1) constraints imposed by the underlying physical layer and 2) QoS requirements. Furthermore, we study how information about the underlying channel quality can be incorporated into the scheduler to improve network performance. Simulations illustrate the merits of our designs. [ABSTRACT FROM PUBLISHER]

In wireless cellular communications, accurate local mean (shadow) power estimation performed at a mobile station is important for use in power control, handoff, and adaptive transmission. Window-based weighted sample average shadow power estimators are commonly used due to their simplicity. In practice, the performance of these estimators degrades severely when the window size deviates beyond a certain range. The optimal window size for window-based estimators is hard to determine and track in practice due to the continuously changing fading environment. Based on a first-order autoregressive model of the shadow process, we propose a scalar Kalman-filter-based approach for improved local mean power estimation, with only slightly increased computational complexity. Our analysis and experiments show promising results. [ABSTRACT FROM PUBLISHER]

Proposes a hybrid approach that effectively combines the best of both nonlinear regression and nonlinear regularization and can be efficiently implemented via the Viterbi algorithm. Weak continuity with structural constraints; Specific instance of RC-weak continuity (WC); Conclusions.