In mobility management, detection of spectrum hole plays very important role for doing spectrum handoff mechanism. Operation of the cognitive radio depends on the spectrum sensing which is the most important task in case of cognitive radio network. Detection of spectrum holes (underutilized sub-bands of the radio spectrum) estimates average power, throughput and utilized time for each spectrum ...

We investigate the performance of handoff policies for data services and voice services in a DS-CDMA system with respect to delay sensitivity. A slotted ALOHA random access scheme on the reverse link is employed to support data services. A soft handoff policy, hard handoff policy and restricted-transmission policy for data packets in a soft handoff region are compared in terms of throughput, sy...

Handoff algorithms are used in wireless cellular systems to decide when and to which base station to handoff. Traditional handoff algorithms generally cannot keep both the average number of unnecessary handoffs and the handoff decision delay low. They do not exploit the relative constancy of path loss and shadow fading effects at any given location around a base station. However, handoff algori...

0163-6804/99/$10.00 © 1999 IEEE ith the increasing demands for mobile multimedia services, future wireless networks will adopt micro/picocellular architectures in order to provide the higher capacity needed to support broadband services under the limited radio spectrum [1]. Due to its flexible bandwidth allocation, efficient multiplexing of bursty traffic, and provision of a wide range of wirel...

a process of transferring a mobile station (MS) from one base station (BS) or channel to another. The channel change due to handoff may be through a time slot, frequency band, codeword, or combination of these for time-division multiple access (TDMA), frequency division multiple access (FDMA), code-division multiple access (CDMA), or a hybrid scheme, respectively [1]. This article includes four...

This paper proposes a Mobile IP Handoff optimization scheme for heterogeneous wireless sensor networks. In the scheme, a complete solution is provided; and handoff can be effectively controlled, the network business environment can be real-time detected; the target network, the handoff type and time can be accurately judged. In addition, the handoff performance of mobile IP will be largely impr...

Both physicians and patients want deeply healing doctor-patient relationships. Too often, though, the ever-expanding demands of medical practice combine with the defenses of the patient to create doctor-patient isolation. Eastern and Western cosmologies and traditions may encourage different approaches to human interaction and healing. At times, probing the patient with more questions may open ...

Many analytical approaches have been proposed for handoff analysis based on hard handoff in mobile communication systems. In code-division multiple-access (CDMA) systems with soft handoff, mobile stations (MS’s) within a soft-handoff region (SR) use multiple radio channels and receive their signals from multiple base stations (BS’s) simultaneously. Therefore, SR’s should be considered for hando...