Monthly Archives: June 2013

60 GHz Wireless Communications: Emerging Requirements and Design Recommendations

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Abstract: Multiple GHz of internationally available, unlicensed spectrum surrounding the 60 GHz carrier frequency has the ability to accommodate high-throughput wireless communications. While the size and availability of this free spectrum make it very attractive for wireless applications, 60 GHz implementations must overcome many challenges. For example, the high attenuation and directional nature of the 60 GHz wireless channel as well as limited gain amplifiers and excessive phase noise in 60 GHz transceivers are explicit implementation difficulties. The challenges associated with this channel motivate commercial deployment of short-range wireless local area networks, wireless personal area networks, and vehicular networks. In this paper we detail design tradeoffs for algorithms in the 60 GHz physical layer including modulation, equalization, and space-time processing. The discussion is enhanced by considering the limitations in circuit design, characteristics of the effective wireless channel (including antennas), and performance requirements to support current and next generation 60 GHz wireless communication applications.

by Kuma CTO Robert Daniels and CINO Robert Heath, Jr.
Copyright 2007 IEEE. Reprinted from IEEE Vehicular Technology Mag., v. 2, no. 3, pp. 41-50, Sep. 2007.

60 GHz Wireless: Up Close and Personal

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Introduction: The millimeter-wave band, especially the unlicensed spectrum at the 60 GHz carrier frequency, is at the spectral frontier of high-bandwidth commercial wireless communication systems. Compared with microwave band communication, spectrum at 60 GHz is plentiful (frequencies of 57–64 GHz are available in North America and Korea, 59–66 GHz in Europe and Japan [1], [2]), but attenuation is more severe (20 dB larger free space path loss due to the order of magnitude increase in carrier frequency, 5–30 dB/km due to atmospheric conditions [3], and higher loss in common building materials [4]). These characteristics make 60 GHz communication most suitable for close-range applications of gigabit wireless data transfer.

by Kuma CTO Robert Daniels, CINO Robert Heath, Jr., et al.
Copyright 2010 IEEE. Reprinted from IEEE Microwave Mag., pp. S44-S50, Dec. 2010.

The Future of WiMAX: Multihop Relaying with IEEE 802.16j

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Abstract: Relaying and cooperation have re-emerged as important research topics in wireless communication over the past half-decade. Although multihop relaying for coverage extension in wireless networks is an old concept, it became practical only recently. Nowhere is this better illustrated than in the IEEE 802.16 working group, which has devoted a task group to incorporating relay capabilities in the foundation of mobile WiMAX-IEEE 802.16e-2005. Currently, this task group is in the process of finishing IEEE 802.16j, the Multihop Relay Specification for 802.16. This amendment will be fully compatible with 802.16e-2005 mobile and subscriber stations, but a BS specific to 802.16j will be required for relays to operate. This article presents an introduction to the upcoming IEEE 802.16j amendment and provides insight about the obstacles that practical system designers face when incorporating relaying into a wireless broadband network.

by Kuma CEO Steven Peters and CINO Robert Heath, Jr.
Copyright 2009 IEEE. Reprinted from IEEE Communications Mag., v. 47, no. 1, pp. 104-111, Jan. 2009.

A Current Perspective on Distributed Antenna Systems for the Downlink of Cellular Systems

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Abstract: Providing uniformly high capacity in cellular systems is challenging due to fading, path loss, and interference. A partial solution to this problem is the deployment of distributed antenna systems, where transmission points are distributed throughout the cell using coax cable or fiber, instead of being centrally located on a single tower. This article reviews how distributed antenna systems are evolving to provide higher performance on the downlink in cellular systems. Research trends in distributed antennas for the downlink of cellular systems are described along with current progress on their integration into commercial wireless cellular standards. A key observation is that distributed antenna systems are tightly integrated into the cellular architecture, and incorporate physical layer technologies like MIMO communication and multiuser MIMO to provide higher data rates.

by Kuma CINO Robert Heath, Jr., CEO Steven W. Peters, et al.
Copyright 2013 IEEE. Reprinted from IEEE Wireless Mag., Apr. 2013.