An Alternative Architecture for WLAN/GPRS Integration

In this paper, we propose a new WLAN/GPRS integration architecture from the point of view of a GPRS operator's WLAN implementation. We introduce a new node, called serving GPRS access router (SGAR), and its associated protocol stack. SGAR acts as WLAN's access gateway to GPRS network so that a mobile terminal (MT) can use GPRS control signaling in WLAN networks in both tight and loose coupling modes. This avoids the requirements of extensible authentication protocol (EAP), implementing RADIUS servers and using expensive SS7 signaling link. NS-2 based simulation results show that the handoff delay in the proposed SGAR based integration technique is considerably less than that with RADIUS based authentication, under increasing packet sizes and/or increasing numbers of transmitting GPRS MTs. In fact, SGAR based tight coupling reduces the latency significantly, as shown in our experimentations.