Digital Signal Processing Reference
In-Depth Information
Figure 13-1.
The 802.11b ad hoc network scenario.
send traffic to and is not within the range of then the information is sent to
one of neighbors, say Node will forward that information to its neighbor,
and so on, until it reaches the destination, In this example, acts as a router.
As a reference scenario, we consider an ad hoc network including one station
generating video traffic, and up to eight stations which generate data traffic. The
overall network scenario is shown in Figure 13-1. All sources are associated with
the same destination and use the same relay stations to deliver their traffic to the
destination. While all sources are in the radio proximity of each other, only
the first relay station can communicate with the destination node, possibly by
using other intermediate relay nodes. A routing algorithm specifically designed
for wireless ad hoc networks, such as DSR [6] or AODV [12], can be used to
establish a route for each source-destination pair.
At the MAC and physical layers, all stations employ the 802.11b functions.
In particular, we assume that all stations can transmit at 11 Mbps and access the
channel by using the basic 802.11b MAC scheme, the so-called Distributed Co-
ordination Function (DCF) [1]. According to DCF, wireless stations wishing to
transmit a MAC Protocol Data Unit (MPDU) employ a CSMA/CA mechanism,
based on the listening-before-transmitting criterion. A station's transmission
