The mobile and wireless communication technologies could play a significant role for the provision of value added services related to the cultural heritage and the fruition of tourist related navigation services. In reality wireless communications may be exploited through the provision of Location Based Services and complement the sattelite positioning systems for delivering innovative applications to the end users.

GSM
GSM (Global System for Mobile communication) is a digital mobile telephone system that is widely used in Europe and other parts of the world. GSM uses a variation of time division multiple access (TDMA) and is the most widely used of the three digital wireless telephone technologies (TDMA, GSM, and CDMA). GSM digitizes and compresses data, then sends it down a channel with two other streams of user data, each in its own time slot. It operates at either the 900 MHz or 1800 MHz frequency band.
While GSM provides excellent and well established voice services, its low transfer rates for data communications (up to 9600Kbps) make it inappropriate for LBS provisioning systems.

GPRS
The GPRS system interworks with the GSM in a complementary way offering data services to mobile users. The data services are implemented in packet-switched way and the data rates achieved are higher than the typical 9.6Kbps circuit-switched transmission of GSM system. The exact data rates depend on the network resources (timeslots available, switching centers), the terminal capabilities (code modulation scheme) as well as the application (ftp, etc.). Most European Mobile Network Operators support CS-2 that provides maximum throughput 48Kbps. In general the GPRS is asymmetric providing lower bitrate in the uplink and higher in the downlink. Both the throughput and the grade of asymmetry are determined mainly from the terminal capabilities.
Currently, almost all commercial terminal support GPRS connectivity.
The basic components of a GSM/GPRS network are defined below.
Mobile stations are registered in the radio network, which constitutes from BTS (Base Transceiver Stations) and the antennas in field. The BTS houses the radio transceivers that define a cell and handles the radio-link protocols with the Mobile Station. The way the BTS’s are lined up make them form cells. Every BTS serves a cell, a single place on earth can be covered by one or multiple cells. The BSC (Base Station Controller), manages the radio resources for one or more BTSs. It handles radio-channel set-up, frequency hopping, and handovers. The MSC (Mobile services Switching Center), acts like a normal switching node of the PSTN or ISDN, and additionally provides all the functionality needed to handle a mobile subscriber, such as registration, authentication, location updating, handovers, and call routing to a roaming subscriber.
The HLR (Home Location Register) holds the information regarding subscriber’s data as well as the users’ current location (VLR address and SGSN address). This is the place where all relevant (temporary) parameters of a Mobile Station are being stored, for each mobile currently located in the geographical area controlled by the VLR.
The SGSN (Serving GPRS Support Node) is another newtwork node related to Packet Switched services. Its tasks include routing, ciphering and authentication, session management, mobility management, generation of billing information.
The GGSN (Gateway GPRS Support None) is an interface towards external IP networks. Its tasks include data formats translation, protocol signalling and addressing information between different networks. The GGSN also generates billing information.

Wireless LAN

A wireless local-area network (WLAN) uses Radio Frequency (RF) technology to transmit and receive data over the air, providing all the features and benefits of traditional LAN technologies but without the limitations of a cable. A WLAN is a flexible data communication system implemented as an extension to, or an alternative for, a wired LAN. Thus, wireless LANs combine data connectivity with user mobility. Most WLANs today use the 2.4GHz frequency band, but the 5GHz is rapidly emerging. Two main types of hardware form the basis of the wireless network:
Network Interface Cards (NICs): In a wireless LAN, NICs provide the interface between the client’s system and the wireless access point, to create a transparent connection to the network.
Access Points: The access point (AP) is the wireless equivalent of a hub. An AP is typically connected with the wired LAN backbone through a standard Ethernet cable, and communicates with wireless devices by means of an antenna. A wireless access point maintains the connections of its clients across its area of coverage permitting or denying specific traffic or clients from communicating through it.
In a typical wireless LAN configuration, the access point connects to the wired network from a fixed location using standard cabling. The access point receives and transmits data between the wireless LAN and the wired network infrastructure. A single access point can support a small group of users and can function within a range of up to several tens meters. End users access the wireless LAN through the wireless-LAN adapters installed in their devices.

Benefits of Wireless LANs

Cost: Wireless LANs can cost less to implement than wired LANs, especially in situations where implementing a wired LAN requires extensive labour and materials to install the wiring and drops. For environments that are difficult to wire (such as schools or temporary spaces) a wireless network can be more cost-effective in the long run than a wired one.
Simple/flexible to Install: Wireless LANs eliminate the time needed with wired LANs for laying and pulling wires, and can reach places that cannot be reached by wires.
Portability: Wireless LAN systems can move physical locations much easier than wired LANs, reducing total cost of ownership for organizations that are on the move.
Mobility: Wireless LAN systems can provide LAN users with access to network information anywhere in their organization.
Scalability: Wireless LAN systems can be configured for small and large offices, with peer-to-peer systems or large established LANs, specific to the localized need of a workgroup or across the whole enterprise. Wireless LAN systems grow easily with the need by adding more access points, client LAN adaptors and extension points. Wireless can be a good solution if you need to connect several buildings without installing a wired connection. Wireless LAN bridges can extend LANs that are typically one to five miles apart. These wireless bridges span multiple-building LANs without incurring the monthly costs of a T1 or higher speed lines.
Positioning: WLAN can save cost and complexity by providing both a communication medium and a positioning technology.

Drawbacks of Wireless LANs

Cost: In environments with installed wiring or less demanding wiring needs, the up front costs of adopting a wireless LAN system can be more expensive than with wired LANs.
Interoperability: There are several competing technologies used by wireless LAN vendors to communicate data between hardware, with no ability for communication directly between systems using these different standards.
Interference: Most of the wireless devices today operate on 2.4-GHz radio bands, which are also used by cordless phones and most microwave ovens. The potential for interference when used near other devices sharing the same frequency band.
Speed: Most commonly used wireless LAN products are rated for a maximum 11Mbps throughput, and in practice see speeds about 80% less than this – some wireless LAN products are rated for speeds much less than this (HomeRF systems for example). Still quite speedy for most network needs and for broadband Internet sharing, but for larger offices with high network traffic and demands for speed, this should be taken into consideration.