The XMAX technology is a application for Android, as a physical layer based technology, which can be used for used in wired and wireless products. It allows end users to make high quality voice over Internet protocol (VoIP) calls using the cognitive radio network. xMax is designed for deploying at any frequency and with configure of licensed and unlicensed spectrum, or in a spectrum sharing fashion. Both voice and SMS text messaging, the application incorporates xG Technology that uses compression algorithms for SIP (session initiation protocol) and high call quality voice is ensured during minimizing bandwidth (over-the-air). Importantly, it improves battery life and range in various applications and radio spectrum is used in a very power effective manner. It carries more reliable VoIP traffic in a smaller channel than various other competing systems
The xMax technology is based on hybrid manner technology in the sense that it has aspects of both wideband and narrowband communication systems. It employs a narrowband carrier and also uses pulse position modulation (PPM) and ultra wideband communications (UWB). xMax is capable of delivering mobile voice over IP (VoIP) and broadband data services in the range of 902-928 MHz in unlicensed band. Thus provide Low-cost mobile voice and broadband data services.
Working of xMax
It is a full-featured voice and SMS application using a modulation technique designed to allow more data to be transmitted over a single sine waves. xMax uses a ratio closer to 1:1 because it uses single sine wave instead of using more than 100,000 sine waves to transmit one bit of data. This technique helps in utilizing power in efficient way (consume low power) . xMax uses frequency channels in the sub-gigahertz range, which can penetrate obstacles such as walls or trees to avoid the distance problem. The built-in dial pad to make new calls is used to support Direct dialling ,we can enter responses to navigate menus or automated attendants in voice response systems. Using the built-in SMS client, SMS messages can be sent. The other possibilities or usage are in enterprise WLANs and metropolitan networks. Nowadays it is used for VoIP.
Structure of Network in xMax
xMax includes responsive opportunistic-use technology which is mainly based on “Identify And Utilize (IAU) techniques capable of in-band interference encountered in the unlicensed spectrum, and extends the RTP and SIP protocols to the wireless domain. SIP is regarded as very bandwidth-inefficient form of signaling overhead. And also SIP signaling can consume up to 400% of the VoIP payload bandwidth, so it is consider as an unacceptable model for mobile networks. To improve the efficiency of SIP signaling, xG has created patent pending with SIP compression technology for the xMax system which reduces SIP overhead bandwidth from 400% to 66% .This provide benefit of making more bandwidth for mobile data applications.
Architecture of xMax Network
As the above figure indicates, the network architecture includes the following basic features:
• xMax is designed for operation in unlicensed as well as licensed bands (Air-interface).
•. The xMax base station is a three sector, where Base station(BSN) provides radio to network access. The BSN channelizes the 902-928 MHz band into 18 discrete channels, which is used for mobile devices that are registered.
• xMSC in an xMax network which provides call process, many other IP, mobility , IP packet delivery services and network signalling functions, where xMSC is based on Access Network Gateway (ANG).
• The special software called Network Monitor (xMonitor) which is responsible for end-to-end network management and monitoring services.
• supports SIP call control, xG’s SIP message compression technology, and E911 services are supported by SIP Proxy Server.
• The private to public network address translation (NAT) services are provided by Firewall.
• IP address services is provided by Proxy DHCP Server .