UDP performance over an ad hoc network for mobile robots

The use of wireless networks has become very popular in the mobile robotics community as they offer many advantages over traditional tethered systems. Wireless networks, however, often suffer from lower throughput and higher packet loss than their wired counterparts. This work attempts to enhance wireless networks used in mobile robotics by determining the optimal packet size for maximum throughput in environments with varying Signal to Noise Ratios (SNRs) where packet loss has started to occur, but has not yet reached 100%. Data recorded by a UDP based Java program was used to calculate the throughput, packet loss, time with signal, and average SNR of packets sent from one stationary node to another in an ad hoc network. Data was taken for ten packet sizes (16, 48, 144, 272, 528, 784, 1040, 1296, 1484, and 1500 bytes) in four SNR zones (4-7, 7-10, 9-12, and 14-18 dB) in two environments (a multi-story building and an open road). Results indicate that a packet size of 784 bytes is optimal for environments in which the signal to noise ratio ranges between 4-18 dB. Future work focuses on incorporating the results of this experiment into an autonomous program for wireless mobile robots that monitors SNR and packet throughput and adjusts the size of the packets accordingly.