RObust Header Compression (ROHC) Performance for Multimedia Transmission over 3G/4G Wireless Networks

RObust Header Compression (ROHC) has recently been proposed to reduce<br>the large protocol header overhead when transmitting voice and other<br>continuous media over IP based protocol stacks in wireless networks.<br>In this paper we evaluate the real-time transmission of GSM encoded<br>voice and H.26L encoded video with ROHC over a wireless link. For<br>the voice transmission we examine the impact of ROHC on the consumed<br>bandwidth, the voice quality, and the delay jitter in the voice signal.<br>We find that for a wide range of error probabilities on the wireless<br>link, ROHC roughly cuts the bandwidth required for the transmission<br>of GSM encoded voice in half. In addition, ROHC improves the voice<br>quality compared to transmissions without ROHC, especially for large<br>bit error probabilities on the wireless link. The improvement reaches<br>0.26 on the 5-point Mean Opinion Score for a bit error probability<br>of 10-3. For the video transmission we examine the impact of ROHC<br>on the consumed bandwidth.We find that the bandwidth savings with<br>ROHC depend on the quantization scale used for the video encoding<br>and the video content and ranges between 5–40% for typical scenarios.