Home Location Register is a database that contains data regarding authorized subscribers using a global system for mobile communication core network.

High speed downlink packet access (HSDPA), also known as 3.5G is an improved third generation telecommunication protocol.

Half Duplex (HDX) is a type of communication system. In half duplex, there is a two-way communication between the sender and the receiver.

In cellular networks, base stations have a limited reach, to achieve connectivity between mobile devices – which are mostly on the move – handover is necessary.

The Home Public Mobile Network (HPMN) is the network of an operator in which a mobile subscriber has a subscription.