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Abstract-This paper examines the temporal characteristics of the fixed wireless access channel resulting from the combined effects of foliage and wind. Measurements at a frequency of 3.5 GHz taken over the course of one year are presented. The temporal variability of the path loss is shown to be well approximated by a Rician process. The dependency of the median K factor on excess path loss, average wind speed and season is investigated. An empirical expression for the median K factor encompassing these variables is presented. The median K factor is found to be approximately inversely proportional to average wind speed.

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BT has embarked on an ambitious and innovative programme to replace its current core network with an all-IP next generation network (NGN) known as 21CN. One of the important properties of an NGN is to allow new and innovative services to be created and deployed quickly, easily and cost effectively. However, managing the sheer number of services, be they generated in-house or by a third party, that will be hosted on such an NGN is not a trivial task. The process of service orchestration (i.e. service blending) is complex and the major standards bodies have, as yet, been unable to define a suitable method. One of the contenders for the role of service orchestration is the Alcatel-Lucent Service Broker TM . BT has been engaged with Alcatel-Lucent during the past year on a proof of concept demonstration to test the Alcatel-Lucent Service Broker's suitability for this role. The findings have shown that this development can support and aid rapid service creation and blending while providing excellent levels of flexibility and programmability. IntroductionBT is already well on the way to converting its existing core network infrastructure to a next generation network (NGN) based on the Internet protocol (IP) and known as the 21st Century Network (21CN). NGNs such as 21CN offer communications operators a number of benefits, not least a reduction in operating costs [1], and a platform that allows new and innovative services to be developed and launched quickly and in a cost-effective way. In the past, new services have largely required independent platforms, each having common features such as billing and customer profile maintenance, often using different protocols. The result is a complex arrangement of networks and platforms involving a myriad of stove-pipe solutions. In contrast, NGNs such as 21CN, offer a common platform that can be used by all applications and services. Commonly used features can be aggregated into common capabilities (CC) [2], and currently there are 12 CCs in the 21CN architecture that can be reused across applications.The common platform allows new services to reuse previously developed functionality, reducing time to market and development costs. It is also possible to look beyond the 'walled garden' architecture that has been the norm and allow third parties to develop and provide services to customers.An important part of the BT NGN architecture is the IP multimedia subsystem (IMS) [3], defined originally as the core network for 3rd generation (3G) mobile systems by the 3rd Generation Partnership Project (3GPP). The IMS was first introduced in the Release 5 (R5) of the 3GPP set of standards. Later releases of the 3GPP standard included interfaces with wireless LAN systems (in R6) and fixed line systems (in R7), paving the way for fixed-mobile convergence (FMC) and providing for new levels of convergence and mobility. A typical scenario might, for example, allow a user to have a single profile for both fixed and mobile services, combining multiple devices. As such, the IMS will herald a new era...

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