Common use of Expanded Cooperation Areas Clause in Contracts

Expanded Cooperation Areas. A need for expanding or enlarging cooperation areas can be motivated in different ways. One goal is to increase the pentration rate of user-centric served CoMP UEs just based on combinatorial considerations. For example, the probability of finding 3 UEs having the same set of 3 strongest cells is very low. An enlarged cooperation area of e.g. 9 cells formed by 3 sites (see as example the right-hand part of Figure 5.2) will already cover 84 potential 3-cell clusters. Any UE having its 3 strongest downlink channels from the 9 cells within this cooperation area can therefore be served user-centric. For this reason, use of clusters of more than 3 cells is a typically provides only moderate to minor gains. Optimization will just find less bad cell sets without solving the issue fundamentally, i.e. finding a clustering where all or nearly all users are served user- centric from their n (e.g. n=3) strongest cell. first step to combine the benefits of static network-centric clustering with the gains of user- centric cooperation.14 In the main scenario used in the present chapter, the cooperation areas have been expanded to 3 sites comprising 9 cells. From a practical point of view, this is an interesting choice. Use of intra-site cooperation only is not sufficient to exploit the interesting CoMP gains for cell edge UEs, located between two different sites and suffering from low received power. Connecting to the nearest adjacent two sites is then the natural first step to inter-site cooperation. As soon as one cell of an adjacent site is included into the cooperation area, the other cells of that site can be incorporated into the cooperation area easily, at least from a backhaul point of view. It is furthermore of potential practical advantage that intra-cluster coordination will only use backhaul connections between nearest neighbouring sites.