TABLE OF CONTENTS In this chapter, we have seen that a number of advanced RRM functions are needed in today's wireless systems, which are being developed and standardized in particular for the 3GPP LTE networks in order to fulfill the ever-increasing capacity demands by utilizing the radio interface more efficiently. Considering the facts that the available radio spectrum is a limited resource and the capacity of a single radio channel between the UE and the network is also limited by the well-known theoretical bounds of Shannon, the remaining possibilities to increase the capacity are to increase the number of such "independent" radio channels in addition to trying to approach the theoretical channel capacity limits on each of these individual channels. Advanced radio resource management techniques play a key role in achieving these goals.
A straightforward way of increasing the number of such "independent" channels is to increase the system bandwidth or the number of cells in a given deployment. In LTE the maximum supported system bandwidth size has been increased to 20 MHz and a variety of flexible system bandwidth configurations is possible; the number of cells in a network is more of a deployment issue than a system design principle. The other, and less straightforward, possibility for increasing the number of independent radio channels is to employ various spatial multiplexing techniques and advanced receiver structures that can better separate out the radio channels in the spatial domain. As we have seen in this chapter, LTE employs all of the preceding...
