This section summarizes the results of initial timing experiments that were undertaken to examine the performance of the orderwire system. The experiments involved determining the time required to transmit and process each of the packet types listed in Table 1 using the real packet radios. These times represent the time to packetize, transmit, receive, and depacketize each packet at the Network Control Protocol process. Figure 12 illustrates the physical configuration used for the experiments involving the real packet radios. The results are presented in Table 2. Most of the overhead occurs during the initial system configuration which occurs only once as long as ESs remain stationary. With regard to a handoff, the 473 millisecond time to transmit and process the handoff packet is on the same order of time as that required to compute the beam angles and steer the beams. The following sections provide an analysis and discuss the impact of scaling up the system on the configuration time.
Figure 12: Physical Setup for Packet Radio Timing.
Table 2: Network Control Protocol Timing Results.