Investigations of cross-layer designs for mobile ad hoc networks

This paper explores the attributes, layering models and objective functions in cross layer designs for mobile ad hoc wireless networks by taking all the statistical characteristics and constraints from the physical (PHY) layer, media access control (MAC) layer and network (NET) layer into consideration. This paper reviews the entire network optimization across all the PHY/MAC/NET layers. At the PHY layer, the adaptive modulation, adaptive channel allocation and adaptive power control are employed according to the channel conditions and different quality of service (QoS) requirements of different services. The PHY layer constraint is specified in terms of target signal to noise and interference ratio (SINR) or target bit-error-ratio (BER). At the MAC layer, a feasible scheduling policy that maximizes the overall system performance for given fairness/QoS requirements is explored through the utility functions that build a bridge between the PHY layer and MAC layer to balance the efficiency and fairness. At the NET layer, the QoS requirements include call blocking probabilities, call connection delays, packet congestion probabilities and packet loss rates. By interacting with PHY layer and MAC layer constraints, a long-term network performance is investigated at the NET layer subject to both call-level and packet-level QoS requirements.