Enabling network redundancy in the radio access network

In the current UTRAN (UMTS terrestrial radio access network) architecture, redundancy is one of the major issues, usually provided by means of robust network elements with high reliability and protection switching in the transport network. When the radio access network evolves to a more distributed architecture, the functions of the RNC (radio network controller) are split according to control and user plane and functional scope (cell, user, multi-cell). In such a way, the network topology becomes more complex, and the contribution of the transmission network becomes a much more important part of the network reliability. A certain availability of single nodes is still needed, which may require also the application of node redundancy mechanisms. In such an access network, there are certain nodes that are location-independent, of a distributed (nonhierarchical) topology and with less stringent delay requirements. For these types of new nodes, network redundancy and the pooling of server nodes promises to be a good alternative to provide reliability in the radio access network.