WiBro (Wireless Broadband Internet), the Korean version of mobile WiMAX compatible standard, provides high-speed mobile data service. Although mobile WiMAX services are being deployed, there exist few reports about WiBro performance. In this work, we measure and analyze best-case performance of WiBro. In order to measure one-way delay, we develop a GPS synchronization device to measure one-way delay.

Our measurement shows that the maximum throughput over the WiBro network is 10 Mbps in downlink and 2.5 Mbps in uplink. We estimate that both the base station and WiBro modems have large buffers up to 2 s and 500 ms and minimum one-way delay of 76 ms and 11 ms for uplink and downlink, respectively. We measure TCP throughput over WiBro by varying the send buffer and receive buffer sizes. To fully exploit the high bandwidth of Wibro, we conclude the TCP needs along with the minimum of 128 KB buffer size.