23-04-2012, 04:23 PM
VOICE OVER IP MOBLIE TELEPHONY USING WIFI P2P
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.INTRODUCTION
The support of telephony services over mobile phone has been used everywhere using technology such as GSM (Global System for Mobile) and 3rd Generation mobile telecommunication 3G [13], but at high cost. On the other hand, IP telephony try to reduce the cost for supporting this service over mobile phone, but it is facing difficulties since the same feature is supported on desktop and laptop at lower complexity. The challenge is to provide the same service over mobile phone at no cost, as it has been described in this paper. Two approaches are suggested in this paper to meet the objective of having free telephony services over mobile phones. These are the use of WIFI technology [14] over AP, and WIFI over p2p (Peer-to-Peer). In addition, a novel algorithm has been invented to tackle the first fundamental problem of designing Ad hoc and p2p telephony using WIFI, which will not rely on any central database, and will not require users to register to any service.
MOBILE CALL USING WIFI TELEPHONY
Wi-Fi telephony, also known as Voice over wireless LAN (VoWLAN), delivers the all the capabilities and functionality of the enterprise telephone system in a mobile handset. The Wi-Fi phone is a WLAN client device, sharing the same wireless network as laptops and PDAs. The handset is functionally equivalent to a wired desk phone, giving end-users all the features they are used to having in a wired office phone. The benefits of VoWLAN can result in substantial cost savings over other wireless technologies by leveraging the Wi-Fi infrastructure and by eliminating recurring charges associated with the use of public cellular networks. For end users, VoWLAN enables employee mobility, resulting in increased responsiveness and productivity.
MOBILE IP CONVERSION ALGORITHM
A software solution was developed in order to convert mobile numbers to IP addresses and vice versa. In this program development, it is possible to map the mobile numbers to a valid IPv6 address, and therefore there is no need for DNS lookup. In addition, there is no need for complicated hashing and addressing protocols because the IP-to-Mobile algorithm would produce a unique number used as input, leading to a unique output hexadecimal IPv6 address. The outputted address is then allocated to private IP within a specified range in order not to conflict with other devices in the same wireless range.
A.Traditional Hashing Algorithm for IP
N is the size of IP range, which should be a prime number larger than our range in order to assure good performance for the algorithm. Consider every IP address as a quadruple of integers modulo N which in IP addresses are 32-bit which quadruple 8- bit. We can define function H for hashing of number mod N, and fix any four coefficients such that Ha (x1,x2,x3,x4) = (a1 × x1, a2 × x2, a3 × x3, a4× x4) mod N[11].
B. Mobile to IP Algorithm and Pseudo code
This algorithm will map any mobile number to a unique IPv6 address, where X10 is {x|1,000,000,000≤ x ≤ 9,999,999,999) base 10 decimal integer and the function f(x) converts X base10 to X base 16 Hexadecimal integer with range{ x|3B9ACA00 ≤ x≤2540BE3FF} as defined in the pseudo code of MobToIP.
CONCLUSION
Voice over WIFI telephony is a challenging research topic. In this paper a novel architecture has been proposed and a novel algorithm has been developed to support IP to Mobile number conversion. The system is transparent to the user, where a user needs only to dial the required phone number the same way of using the normal mobile phone. Following the mobile conversion to IPv6, the software applied at the mobile phone will try to establish p2p connection to the dialed mobile phone using the same algorithm.