Roaming in Wireless Networks

Roaming is one of the most popular features offered by wireless networks today. For mobile users, it offers the ability to use the mobile services outside their service provider’s coverage area with the same phone. For service providers, roaming offers an opportunity to serve visitors from foreign networks as well as their own subscribers anywhere […]

Interstandard Roaming

Interstandard, or cross-technology, roaming refers to roaming capabilities between two networks regardless of technology and standards. From business and user satisfaction points of view, interstandard roaming capabilities are required to further expand roaming services. The incompatibility in standards makes it difficult to enable roaming between networks. For example, second-generation networks are predominantly based on the […]

Prepaid and Postpaid Subscriber Roaming

International roaming allows a subscriber to access services virtually anywhere in the world. The visited network obviously needs to charge foreign subscribers for access time, transport and services. As the visited network is not in position to directly bill the roamers, it invoices their home network for the services usage. The home network then charge […]

Basic Structure of Roaming

In order to enable roaming, following basic structure should be in place: 1. Inter-PLMN connection. With reference to Figure 1-2, this connection consists of: (a) CCS7 links (for SCCP MAP traffic) between the VPLMN and the HPLMN. These links are required for information exchange between the HLR in the home network and the VLR in […]

Roaming Services

The service a roamer enjoys in a visited network depends on three factors: mobile station (MS) capabilities, the agreed list of services in the roaming agreement, and the subscription level. Commercially available handsets generally support the following network capabilities: ■ GSM ■ GSM + GPRS ■ GSM + GPRS +3G A complete list of services […]

Signaling—An Introduction (CCS7 in Wireless Networks)

Common Channel Signaling System no. 7 (CCS7) was initially designed for fixed line networks. As we will learn in the following topics, CCS7 is also a basis for signaling traffic in the GSM core network and plays an important role in 3G networks after suitable adaptation. An understanding of CCS7 is required to grasp the […]

CCS7 Network Architecture

The CCS7 network is a logically separate network within a telecommunication network. It consists of signaling points or signaling nodes connected with the signaling links. The CCS7 network has four distinct signaling points. Service signaling points (SSPs) are network nodes that generate signaling messages to transfer call- or transaction- (non-call-) related information between different CCS7 […]

Message Transfer Part (CCS7 in Wireless Networks)

MTP Level 1 The Signaling Data Link corresponds to the Physical Layer of the OSI model. It defines the physical and the electrical characteristics of the signaling link, connecting two signaling nodes. The Signaling Data Link is a bidirectional physical connection. The physical interfaces initially defined by ITU-T include: ■ E1, 2.048 Mb/s, 64-Kb/s channel […]

ISDN User Part (CCS7 in Wireless Networks)

Integrated Services Digital Network User Part (ISUP) provides the signaling functions required to control circuit-switched voice/data calls and supplementary services. ISUP is also used extensively in the GSM core network for controlling calls between MSCs and between the GMSCs and the external PSTN. ISUP call control is achieved by the exchange of ISUP messages. These […]

Signaling Connection and Control Part (CCS7 in Wireless Networks)

The SCCP supplements the MTP transport capabilities to provide enhanced connectionless and connection-oriented network services. Together with the MTP, it provides the capabilities corresponding to Layers 1 to 3 of the OSI model. The combined MTP and SCCP services are called the Network Service Part (NSP). The SCCP structure is illustrated in Figure 2-10. As […]