This thesis describes the design and development of the SmartBadge; an electronic replacement for the standard paper name badge worn at conferences and similar events. Both hardware and software have been designed for the SmartBadge; the hardware has been developed around a CC1010 microcontroller and RF transceiver. Attached to this are an infrared transceiver, an LCD display, some LEDs, buttons and a piezoelectric buzzer. There is also an antenna for the RF transceiver whose design is the result of SuperNEC [1] simulations. Protocol software development has focussed on the communication between a SmartBadge and other badges and base stations, yet there is still space available in the CC1010s flash memory to develop applications beyond the business card exchange example developed to demonstrate the communication software. The SmartBadge communicates with other badges by using the infrared transceiver. In the business card application a SmartBadge is worn by a person and is collecting the ID and a time counter from SmartBadges worn by other facing people as this person mingles through a conference or similar event. This data is then collected in real time using the RF transceiver to communicate with base stations which would be scattered around the venue. The RF network has been designed as a single hop network and a new Medium Access Control (MAC) protocol has been designed to allow the SmartBadges to share the links to the base stations while conserving as much energy as possible. This protocol is called Uplink MAC (or U-MAC) and is described in section 6.2.

Nomadic computing aims to be a leading short term revolution in the Internet, however to succeed in this the infrastructure, the protocols, the handoff mechanisms have to be designed and implemented to provide mobile computing with both reliability and transparency. A good deal of the work is addressed by mobile IP itself, but addressing wireless diversity is perhaps the most important next step. Many different wireless technologies are available; while one technology might provide wide coverage, another provides higher bandwidth, but can only be deployed locally, even uni-directional ad-hoc links can be used to carry IP traffic. To take full advantage of the potential infrastructure, a mobile device, with multiple network interfaces, should be able to dynamically switch from one link technology to another; hopefully totally transparently to the user. Moreover, having multiple interfaces allows the device to choose, each time a new connection is established, which interface to select to route the datagrams through, based on the type of service desired. In this thesis a possible solution is presented, involving both vertical handoff optimization and policy management. Our testing device is the the SmartBadge v4, provided with a GPRS link and a 802.11b WLAN interface. / Nomadic Computing har för avsikt att revolutionera dagens Internet tillämpningar. För att lyckas måste dock infrastrukturen, IT protokollen och handoff procedurer utformas och implementeras med intentionen att förse mobilt dataöverföring med både driftsäkerhet och autonoma processer. En stor del av de nödvändiga förutsättningarna är tillgängliga tack vare Mobile IP, men mångfalden inom de befintliga Wireless teknologierna utgör fortfarande ett problem. Det stora antalet disponibla Wireless tekniker varierar från teknologierer som förser användaren med en stor täckningsgrad, till sådana som förser användaren med högre bandbredd, begränsad till lokala anv ändningområden. Även Uni-directional ad-hoc links kan läggas i denna lista av mångfald. För att förverkliga fördelarna med den tänkta infrastrukturen fullt ut måste den mobila enheten kunna utföra omkopplingar från den ena wireless teknologin till den andra, med syftet att vara osynlig för användaren. Utöver detta är det meningen att en apparat med många anslutningar ska kunna välja den anslutning som passar bäst, var gång en ny koppling ska göras, beroende på den tjänst som efterfrågas. Det här examensarbetet presenterar en möjlig lösning, som utnyttjar både Vertical Handoff optimering och Policy Management. Prototyp-enheten vi anv änder oss av för att genomföra undersökningen är Smart Badge v4, utrustad med GPRS och 802.11b Wireless LAN anslutningar.