In this paper, we present an experimental and simulation based study to evaluate the use of full-duplex as a mode in practical IEEE 802.11 networks. To enable the study, we designed a 20 MHz multi-antenna OFDM full-duplex physical layer and a full-duplex capable MAC protocol which is backward compatible with current 802.11. Our extensive over-the-air experiments, simulations and analysis demonstrate the following two results.First, the use of multiple antennas at the physical layer leads to a higher ergodic throughput than its hardwareequivalent multi-antenna half-duplex counterparts, for SNRs above the median SNR encountered in practical WiFi deployments. Second, the proposed MAC translates the physical layer rate gain into near doubling of throughput for multi-node single-AP networks. The two combined results allow us to conclude that there are potentially significant benefits gained from including a full-duplex mode in future WiFi standards.
Proportional Fair (PF) scheduling algorithms are the de-facto standard in cellular networks. They exploit the users' channel state diversity (induced by fast-fading), and are optimal for stationary channel state distributions and an infinite time-horizon. However, mobile users experience a non-stationary channel, due to slow-fading (on the order of seconds), and are associated with basestations for short periods. Hence, we develop the Predictive Finite-horizon PF Scheduling ((PF) 2 S) Framework that exploits mobility. We present extensive channel measurement results from a 3G network and characterize mobility-induced channel state trends. We show that a user's channel state is highly reproducible and leverage that to develop a data rate prediction mechanism. We then present a few channel allocation estimation algorithms that rely on the prediction mechanism. Our trace-based simulations consider instances of the PF 2 S Framework composed of combinations of prediction and channel allocation estimation algorithms. They indicate that the framework can increase the throughput by 15%-55% compared to traditional PF schedulers, while improving fairness.
This paper represents the technical core of a precompetitive consortium formed by AT&T, DEC and MIT to study the technology, architecture and applications of wide-band alloptical networks of local to national (or international) extent. This effort is currently partially sponsored by the Defense Advanced Research Projects Agency (DARPA). Sections I and I1 of this paper provide a general introduction to all-optical networks and discuss some proposed applications. Sections 111, IV and V cover the architecture, technology and test-bed portions of our effort.
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