Johan Lundsjö

Radio resource management distribution in a beyond 3G multi-radio access architecture

Efficient employment of multiple radio access technologies is expected to be an important property of beyond 3G networks. This will put high demands on radio resource management support, both within and in-between radio access technologies. In this paper we discuss how to distribute radio resource management in a multi-radio access network, and identify three main distribution strategies: network centralized, network distributed and finally the option of having multi-access radio resource management located in the terminal. A combination of network distributed and terminal based radio resource management appears to be the best choice for dynamic multi-access radio resource management in most scenarios. Further, relations towards user plane functions are discussed and modeled, and the functionality is mapped to nodes and interfaces of a beyond 3G reference radio access network architecture.

Beyond 3G radio access network reference architecture

Today a multitude of radio access technologies exist and are continuously evolved to support higher bit rates, lower delays, lower cost, etc. In addition, new radio access technologies are developed to complement those of today. When using services in this environment with multiple radio access technologies, end users expect mobility between the different radio access technologies to be seamless. Network operators, in addition, look for efficient resource usage of different radio access technologies and more cost efficient ways to deploy networks. This requires increased flexibility in the radio access network architecture compared with todays architectures. In this paper a beyond 3G radio access network reference architecture supporting these requirements is presented. The architecture allows for various implementations and considers new deployment concepts such as multi-hop radio networks, moving networks and personal area networks.

A generic link layer in a beyond 3G multi-radio access architecture

A major aspect of beyond 3G networks is the efficient integration of multiple radio access technologies in a common network. One advantage of this multi-radio access integration will be an increased radio resource efficiency, e.g., due to a larger trunking gain and reduced radio cost per link. One realization of the multi-radio access integration is based on a generic link layer, which provides generic data processing for a multitude of radio access technologies. The generic link layer enables fast and lossless access selection. The functional architecture of the generic link layer is discussed, including the separation of radio dependent and radio independent functions. Furthermore, the relationship of the generic link layer to (multi-) radio resource management functions and radio specific transmission functions is presented and an example of access selection is described. Finally, we present how the generic link layer is included into a beyond 3G network architecture.

Integration of multi-radio access in a beyond 3G network

A major aspect of Beyond 3G networks is the efficient integration of multiple radio access technologies in a common network. One advantage of this multi-radio access integration is the increase in radio resource efficiency, e.g. due to a larger trunking gain and reduced radio cost per link. This paper analyses and compares the different ways of how multi-radio access integration can be achieved. In particular, it investigates three multi-radio integration alternatives, two of them solving the problem at the network level and the third one on the link level. The comparison of the different approaches reveals that link level integration allows access path switching on a shorter time scale than network level integration. Another difference is where they allow the multi-radio resource management functions to take place, on network side or on user terminal side. In general, it is concluded that all schemes have certain advantages and disadvantages depending on the considered scenario. It is also highlighted, that these different integration schemes can be combined, i.e. some radio access technologies can be integrated on link level, while others can be integrated on network level.