Security for Multihop Wireless Networks

472  ◾  Security for Multihop Wireless Networks

One of the reasons for deploying cross-layer design is the support for QoS and

security provisioning at the application layer. If no cross-layer feedback parameters

were provided from lower layers, the decisions made at the application layer may not

be optimized due to the lack of real-time network-based information. For instance,

when the transmitter’s signal strength (a physical layer parameter) drops, the sys-

tem’s throughput may decrease dramatically, therefore “knowing” about this drop

at the application layer may be very useful to adapt the multimedia encoder quality

to the channel/signal conditions. is is to avoid using high-data-rate encoding

schemes when the signal strength is relat ...