Date Added: Jan 2010
In heterogeneous architecture vertical handoffs let users have service from both GPRS and WLAN without any session termination and seamless to the end user. In international literature there are many researches trying to propose the merging of WLAN and GPRS networks into one heterogeneous interworking system. The loose coupling and tight coupling approach has been specified by ETSI describing the architecture of operation. Pylarinos et al. in described a possible WLAN-GPRS access network architectured based on 3GPP recommendations and a survey of the interworking in WLAN-GPRS Integration was given in. Louvros also described the high bandwidth user applications emerging from heterogeneous networks.