Cross-layer MIMO-link exploiting packet re-routing mechanisms and adaptive modulation in diverse channel condition

This paper considers a cross-layer adaptive modulation switching concept for TCP-enabled MIMO wireless communication systems implementing a packet re-routing mechanism over physically decomposed sub-channels. We demonstrate that combining both adaptive modulation and packet re-routing mechanisms improve overall performance over MIMO sub-channels that posses unbalanced or uneven time-varying error rate characteristics. A simulated wireless communications system employs and evaluates packet re-routing techniques over four sub-channel connections made available to the link layer. It then considers the effect of cross-layer directed link modulation adaptation switching for point-to-point wireless communications. We investigate the system in the light of goodput under various channel differences and characteristics, including data rate and bit error rate (BER). For each developed scenario, a separate analysis and discussion is presented. Based on the investigation results, we demonstrate that even simple re-routing and adaptive modulation mechanisms may be beneficial for systems utilising multiple antennas.