xMax: Optimized for Mobile VoIP and Data Bandwidth
To meet the objective of providing low-cost mobile voice and broadband data services, the xMax carrier class cognitive radio solution has been developed around commonly used and open Internet protocols including IP, RTP, UDP and IP. In addition, it was designed to operate in both unlicensed spectrum, such as the 902-928 MHz ISM band, and licensed spectrum.
As a result of these design considerations, xMax includes responsive opportunistic-use technology based on “Identify And Utilize (IAU) and interference mitigation (IM) techniques capable of combating in-band interference encountered in the unlicensed spectrum, while extending the SIP and RTP protocols to the wireless domain.
Among VoIP signaling protocols, SIP is regarded as very bandwidth-inefficient from an overhead standpoint. In fact, SIP signaling can consume up to 400% more of the over the air capacity than the VoIP payload (actual voice packets), This is an unacceptable figure for mobile networks.
To increase the efficiency of SIP signaling, yet maintain 100% standards compatibility with external VoIP systems and soft switches, xG has created patent pending SIP compression technology for the xMax system that reduces SIP overhead bandwidth from 400% to 66% on the xMax over the air protocol and backhaul links from the xAP (Access Point) to the xMax MSCs. The MSCs do the SIP compression and decompression to maintain 100% interoperability with third-party VoIP systems. This also has the benefit of making more bandwidth available for mobile data applications being carried alongside voice traffic.