Radio Resource Management
Quality, Capacity and Radio Resource Management
Since the beginning of electronic data transmission the demand for mobility, capacity, quality, and security of communication networks has steadily been increasing. Especially the urge for maximum mobility pushes the developement of wireless communication systems. Various generations of cellular mobile radio networks for speech and data transmission (GSM/GPRS, EDGE, CDMA-2000, UMTS, HSDPA) have been developed as well as different standards for high-rate wireless data transmission (Bluetooth,W-LAN, WiMAX).
For all these systems the capacity is of vital importance: It is bounded by the physical properties of the air interface and the resulting information theoretical limitations for data transmission. However, many users should be able to make use of these systems. Access and modulation techniques like CDMA or OFDM are today's most promising candidates, providing a high degree of flexibility in sharing the radio channel between different numbers of users. These techniques on the other hand demand very sophisticated radio resource management (RRM) methods which have to provide all users with the necessary radio resources such as scrambling or spreading codes (for user seperation) or transmit power.
The influence of different RRM methods on the capacity of mobile radio networks can be derived analytically only for rare simple cases. The analysis of more complex scenarios demands the use of different kinds of simulations. These comprise bit-level simulations of single transmission links as well as system-level simulations of whole radio networks.