Ultra-wideband millimeter-wave (mmWave) propagation measurements were conducted in the 28- and 73-GHz frequency bands in a typical indoor office environment in downtown Brooklyn, New York, on the campus of New York University. The measurements provide large-scale path loss and temporal statistics that will be useful for ultra-dense indoor wireless networks for future mmWave bands. This paper presents the details of measurements that employed a 400 Megachips-per-second broadband sliding correlator channel sounder, using rotatable highly directional horn antennas for both co-polarized and crosspolarized antenna configurations. The measurement environment was a closed-plan in-building scenario that included a line-of-sight and non-line-of-sight corridor, a hallway, a cubicle farm, and adjacent-room communication links. Well-known and new single-frequency and multi-frequency directional and omnidirectional large-scale path loss models are presented and evaluated based on more than 14 000 directional power delay profiles acquired from unique transmitter and receiver antenna pointing angle combinations. Omnidirectional path loss models, synthesized from the directional measurements, are provided for the case of arbitrary polarization coupling, aswell as for the specific cases of co-polarized and cross-polarized antenna orientations. The results show that novel large-scale path loss models provided here are simpler and more physically based compared to previous 3GPP and ITU indoor propagation models that require more model parameters and offer very little additional accuracy and lack a physical basis. Multipath time dispersion statistics formmWave systems using directional antennas are presented for co-polarization, crosspolarization, and combined-polarization scenarios, and show that the multipath root mean square delay spread can be reduced when using transmitter and receiver antenna pointing angles that result in the strongest received power. Raw omnidirectional path loss data and closed-form optimization formulas for all path loss models are given in the Appendices.

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Indoor Office Wideband Millimeter-Wave Propagation Measurements and Channel Models at 28 and 73 GHz for Ultra-Dense 5G Wireless Networks

Wireless access to the Internet is expected to be very valuable for both individuals and the society. However, advances in transmission technology alone may not be sufficient to support the anticip ...

/pdf/cost-effective-deployment-strategies-for-heterogenous-1yvms6cqez.pdf

Cost Effective Deployment Strategies for Heterogenous Wireless Networks

This paper addresses the throughput maximization problem in wireless mesh networks. For the case of cooperative access points, we present a negotiation-based throughput maximization algorithm which adjusts the operating channel and power level among access points automatically, from a game-theoretical perspective. We show that this algorithm converges to the optimal channel and power assignment which yields the maximum overall throughput with arbitrarily high probability. Moreover, we analyze the scenario where access points belong to different regulation entities and hence non-cooperative. The long- term behavior and corresponding performance are investigated and the analytical results are verified by simulations.

/pdf/joint-channel-and-power-allocation-in-wireless-mesh-networks-35g9btpunc.pdf

Joint Channel and Power Allocation in Wireless Mesh Networks: A Game Theoretical Perspective

This work presents a decentralized mobility control algorithm for an optimal end-to-end communication chain using a team of unmanned aircraft acting solely as communication relays. The chaining controller drives the location of a virtual control point, using estimates of the communication objective function gradient calculated using stochastic approximation techniques, to locations of improved relaying for unmanned aircraft. The gradient estimate is derived from observation data of the communication objective function taken along a path generated by the aircraft orbiting about the control point. Flight experiments show that an unmanned aircraft can measure the signal-to-noise-and-interference ratio fields from IEEE 802.11b/g (WiFi) communication links; generate estimates of the field gradients using the least-squares gradient estimation method; and use the gradient estimates to drive a control point to a location that improves communication capacity.

Optimizing Cascaded Chains of Unmanned Aircraft Acting as Communication Relays

Ad hoc wireless multi-hop networks (AHWMNs) are communication networks that consist entirely of wireless nodes, placed together in an ad hoc manner, i.e. with minimal prior planning. All nodes have routing capabilities, and forward data packets for other nodes in multi-hop fashion. Nodes can enter or leave the network at any time, and may be mobile, so that the network topology continuously experiences alterations during deployment. AHWMNs pose substantially different challenges to networking protocols than more traditional wired networks. These challenges arise from the dynamic and unplanned nature of these networks, from the inherent unreliability of wireless communication, from the limited resources available in terms of bandwidth, processing capacity, etc., and from the possibly large scale of these networks. Due to these different challenges, new algorithms are needed at all layers of the network protocol stack. We investigate the issue of adaptive routing in AHWMNs, using ideas from artificial intelligence (AI). Our main source of inspiration is the field of Ant Colony Optimization (ACO). This is a branch of AI that takes its inspiration from the behavior of ants in nature. ACO has been applied to a wide range of different problems, often giving state-of-the-art results. The application of ACO to the problem of routing in AHWMNs is interesting because ACO algorithms tend to provide properties such as adaptivity and robustness, which are needed to deal with the challenges present in AHWMNs. On the other hand, the field of AHWMNs forms an interesting new application domain in which the ideas of ACO can be tested and improved. In particular, we investigate the combination of ACO mechanisms with other techniques from AI to get a powerful algorithm for the problem at hand. We present the AntHocNet routing algorithm, which combines ideas from ACO routing with techniques from dynamic programming and other mechanisms taken from more traditional routing algorithms. The algorithm has a hybrid architecture, combining both reactive and proactive mechanisms. Through a series of simulation tests, we show that for a wide range of different environments and performance metrics, AntHocNet can outperform important reference algorithms in the research area. We provide an extensive investigation of the internal working of the algorithm, and we also carry out a detailed simulation study in a realistic urban environment. Finally, we discuss the implementation of ACO routing algorithms in a real world testbed.

https://doc.rero.ch/record/9027/files/2007INFO001.pdf

Adaptive routing in ad hoc wireless multi-hop networks

Public wireless local-area networks (PWLANs) based on IEEE 802.11 a/b/g standards are growing rapidly. Thus, it is critical to understand aggregated traffic statistics and network performance at and around PWLAN service areas. This paper presents measured PWLAN traffic statistics and application-level throughput at four hotspots that provide free Internet access. The four hotspots, located in Austin, Texas and owned by Schlotzsky's Inc., a national restaurant chain, used standard IEEE 802.11b equipment. This measurement campaign provided approximately 16 million PWLAN packets and several hundred throughput and SNR measurements. Throughput prediction models are developed based upon the measured data. These analysis results and throughput prediction models may facilitate the design and development of IEEE 802.11 e/n standards and implementations. Moreover, the results provide insights into the required provisioning for PWLANs and autonomous control approaches for future broadband wireless access and real-time wireless voice/video services

C. Na

Papers

Measured Traffic Statistics and Throughput of IEEE 802.11b Public WLAN Hotspots with Three Different Applications