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2008 Science Publications Performance Study of Power Control Radio Resource Management Over WLANs
Abstract
Wireless Local Area Networks (WLANs) based on IEEE 802.11 standard have been rapidly growing. With limitations of the WLAN standard and rapid increase in wireless application demand, the air interface acts as bottleneck even in high-speed WLAN standards such as IEEE 802.11a and 802.11g with expected data transmission rates of up to 54 Mbps. To improve the overall performance of IEEE 802.11 WLAN under large deployment and heavy application demand environment, Radio Resource Management (RRM) algorithms based on power control have been investigated and tested through simulation. The results show that controlling the Wireless Terminal’s (WT) transmitter power to an optimum power level helps in increasing data throughput in WLANs and when the transmitter power level of a WT is increased beyond the optimum power level, the overall data throughputs drop drastically no matter how high the WT’s transmitter power may be increased.
In order to achieve higher spectrum utilization and/or better quality of service in cognitive wireless networks, solve the problem of non-convergent by using traditional power control methods, a framework of decentralized power control called Target SIR Curve Based Power Control (TSCBPC) is presented, by setting the SIR target of each wireless station according to the Target SIR Curve, which is specified to reflect the corresponding service requirements. Different curves may lead to different dynamic behaviors and different levels of priority in service. Convergence and feasibility are demonstrated. Simulation results show that the scheme can be applicable to cognitive radio networks to support different QoS (Quality of Service) and priorities for primary and secondary users.
Mobile IP is a proposed standard protocol that builds on the
Internet Protocol by making mobility transparent to applications and
higher level protocols like TCP. Mobile IP (RFC 2002) is a standard
proposed by a working group within the Internet Engineering Task Force;
it allows the mobile node to use two IP addresses: a fixed home address
and a care-of address that changes at each new point of attachment. The
article presents the Mobile IP standard in moderate technical detail and
points the reader toward a wealth of further information. Is also
describes how Mobile IP will change with IP version 6, the product of a
major effort within the IETF to engineer an eventual replacement for the
current version of IP. Although IPv6 will support mobility to a greater
degree than IPv4, it will still need Mobile IP to make mobility
transparent to applications and higher level protocols such as TCP.
There is a great deal of interest in mobile computing and apparently in
Mobile IP as a way to provide for it. A quick Web search for items
related to Mobile IP returned over 60,000 hits-impressive even given the
notorious lack of selectivity for such procedures. Mobile IP forms the
basis either directly or indirectly of many current research efforts and
products. The Cellular Digital Packet Data (CDPD), for example, has
created a widely deployed communications infrastructure based on a
previous draft specification of the protocol. In addition, most major
router vendors have developed implementations for Mobile IP
We investigate a smart antenna based load balancing scheme, which dynamically changes cell size and shapes according to the geographic call traffic distribution over time. The performance of the whole cellular network can be improved by contracting the antenna pattern around the source of peak traffic and expanding adjacent cells coverage to fill in the coverage loss. Our previous work based on scenarios with nonuniformly distributed traffic scenarios has shown the improvement of system capacity of such a dynamical cellular coverage planning scheme exceeds 20%. A negotiation approach for the real-time control of cellular network coverage is described.
The throughput performance of IEEE 802.11 wireless LANs has been
evaluated in relation to overhead. Sources of overhead are gap time,
preamble, header fields for the PHY (physical) and the MAC (medium
access control) layer, ACK (acknowledgement) frames, the TCP
(transmission control protocol). The impact of this overhead can be
modeled. After measuring the net throughput with 2.4 GHz products and
detailed monitoring of actual exchange of frames, this modeling has been
refined. The close fit between the results of measuring and of modeling
for currently available 2.4 GHz product allows an accurate prediction
for enhanced 2.4 GHz versions and new 5 GHz products
This article discusses an evolutionary TDD mode of CDMA-based path for 3.5G/4G systems. This technology has already been the basis of two 3G standards: TD-CDMA and TD-SCDMA with a synchronous uplink. Several techniques have been developed that allow TDD-CDMA-based systems to transmit at rates usually associated with 3.5G to 4G, up to 10-20 Mbit/s with wide area coverage. The present TDD-CDMA-based 3G standards are evolving to provide these higher rates, while fully retaining the coverage and mobility associated with, and expected from, the present mobile communications systems. This article discusses how TDD-CDMA specific techniques facilitate delivering services at data rates associated with 3.5G and 4G. We review how TDD-CDMA can provide for asymmetric uplink and downlink transmissions, facilitate deployment of advanced antennas for improved downlink coverage, and enable provision of advanced receiver techniques in base stations and mobiles. We also discuss how these techniques affect systems capacity in full packet-switched IP-based systems. We then discuss 4G TDD CDMA systems: those with different modulation techniques for uplink and downlink communications. These are generally based on a multicarrier mode of CDMA, and may incorporate OFDM technique.
An agent based approach to controlling resources in UMTS networks
IST Project SHUFFLE, 2001. An agent based
approach to controlling resources in UMTS
networks. last visited on Jan. 2001.
An Introduction to Wireless Technology
- S R Gary
- E John
Gary S. R and E. John. 2000. An Introduction to
Wireless Technology. Prentice Hall.
Advances in 3G Enhanced Technologies for Wireless Communiactions
- W Jiangzhou
- Ng Tung-Sang
Jiangzhou W and Ng. Tung-Sang. 2002. Advances
in 3G Enhanced Technologies for Wireless
Communiactions. Artech House.
Mobile Telecommunications Protocols for Data Networks
- Anna Hac
Anna Hac, 2003. Mobile Telecommunications
Protocols for Data Networks. John Wiley and
Sons, Inc.
Wi-Fi Planet. [last visted on 20
- Gim Geier
Gim Geier, 2003. Wi-Fi Planet. [last visted on 20
June 2005].