Tekniker för höjande av kapaciteten i mobila radionät

The main objectives with this report is to: ? present and describe techniques that have the potential to significantly increase the capacity of tactical ad hoc networks, ? give the reader an understanding for the remaining challenges that need to be solved before incorporating these techniques in future military radio waveforms. The most interesting techniques for increasing the capacity of future military waveforms include: adaptive modulation and coding (ACM) schemes, MIMO-techniques (which uses multiple antennas at both transmitter and receiver), and multiples access control (MAC) schemes utilizing elaborate traffic adaptivity and spatial-reuse techniques. Adaptive modulation/coding and MIMO-techniques are commonly used in civilian systems and standards. However, the achievable capacity gains for typical military peer-to-peer scenarios at 240-400 MHz is still unknown considering realistic conditions, e.g. on real-world urban peer-to-peer communication channels, and with imperfect channel information and channel estimators. Several outstanding research questions regarding adaptive coding and modulation and MIMO are described, and recommendations are given concerning which of these should be targeted by the project. Furthermore, we have identified and discussed the most crucial require-ments and restrictions stemming from the higher layers on the high capacity techniques. Also, some of the most crucial aspects concerning the co-design of ACM, MIMO and MAC algorithms have been identified. It is believed that major protocol modifications are needed in order to efficiently utilize the proposed techniques in mobile ad hoc networks. However, the know-ledge of how to co-design MAC together with MIMO and ACM algorithms for tactical ad hoc networks is rudimentary at this point and this task will require substantial research and development efforts to solve.