Ulrike Korger

  • Citations Per Year
Learn More
System-level simulations of packet-based orthogonal frequency-division multiple access (OFDMA) cellular networks require a proper consideration of the channel-dependent fast fading/scheduling in order to produce meaningful results. However, generating the time and frequency selective fast fading channels and performing detailed channel-adaptive scheduling(More)
In wireless ad hoc networks, multiple access interference is the limiting factor for the overall system performance. The lack of any central control unit necessitates a careful joint design of both, the physical and the MAC layer. Two promising technologies that address this problem are power control based cross-layer design and multiuser detection based(More)
It has long been known that adaptive beamforming has the potential to enhance the performance of wireless ad hoc networks significantly. However, due to the decentralized nature of such infrastructure-less networks, it is not straight forward to fully realize the potential performance gains of beamforming in a realistic manner. To this end we devise a fully(More)
In wireless ad hoc networks, cross-layer design aims at reducing multiple access interference and thus obtaining a higher spatial reuse. In order to identify the most suitable solution for future wireless systems, we compared the aggregate throughput achieved by two types of cross-layer designs. While the first approach suppresses the interference by power(More)
Ad hoc wireless multihop networks inherently suffer from interference when several nodes communicate in parallel in a close vicinity. This problem can be alleviated, if the nodes apply multiple antennas and appropriate techniques like beamforming or layered space-time processing. While such techniques are well studied in cellular networks, it is not(More)
The particular topology found in metropolitan areas can be exploited by employing relay nodes, which turn one-hop non-line-of-sight connections into multi-hop line-of-sight ones, thereby reducing the shadowing. However, this topology should also be considered to avoid multi-user interference and thus exploit the spatial resources optimally. Nevertheless, in(More)
This paper addresses the fairness of Medium Access Control (MAC) protocols that are capable of handling interference on the physical layer to a varying extent. The variation addressed is thereby not based on different physical layer techniques applied, but on differing attribute levels of the same physical layer technique. This can e.g., be a varying number(More)
In order to allow for dense spatial reuse in wireless ad hoc networks, multiple access interference must be dealt with. This calls for advanced physical layer techniques, such as multiuser detection or power control. However, these techniques can only be efficiently applied to ad hoc networks when they are part of a joint PHY/MAC cross-layer design. In(More)
A methodology for comparing MIMO relaying deployment strategies is proposed and a number of strategies are compared in a Manhattan grid scenario. The focus is on the deployments rather than on the type of MIMO technique in use. Therefore, the system behavior is modeled based on the maximum achievable sum rate under a sum power constraint (also known as(More)
  • 1