As a platform and framework Urban Tapestries prototype is intended to be network and device agnostic, i.e. not a product or service designed for a specific brand, technology or service. Ideally it should be able to run on a number of different types of mobile pervasive device (PDAs, smartphones, tablets etc) and to connect to the internet across different networks (GSM, GPRS, UMTS/3G, 802.11x etc). For the public trial we have narrowed the devices down to two: the SonyEricsson P800 and the HP iPAQ 5450, connecting via GPRS and 802.11b respectively.

USER DEVICE
The Urban Tapestries prototype is anticipated to use several different user devices running a Java client application as the browsing and authoring interface to the system. Devices currently being researched include Pocket PC/Windows Mobile, Symbian and PalmOS devices. For the pubic trial we hope to have several different devices with combinations of Bluetooth, 802.11b WiFi, GPRS (General Packet Radio Service) and GPS (Global Positioning System). The system will be scalable for a range of different devices since not all features will be accessible to every type of device.
PUBLIC TRIAL: SonyEricsson P800s running native c++ client over GPRS, and, HP iPAQ 5450s running a FLASH client over 802.11b.

USER INTERFACE
The interface for the client device is likely to have simple and expert modes for people to choose how they wish to use the system. Filtering the content will be done on several levels; users will create Profiles to store different sets of filter preferences that they can switch between; filtering preferences will allow users receive by file type (for exapmple only audio or text files), keywords, author, time etc. Filters will work both as 'exclusions' prohibiting content and as 'inclusions' accepting only specified content.
PUBLIC TRIAL: Interface will focus on authoring mode, with no filters or profiles enabled due to limited duration of each session (2 hours).

LOCATION SENSING
Several location sensing technologies are being investigated, including versions of GPS (Global Positioning System), mobile phone cell triangulation, 802.11 node proximity and direct user input (via a visual map, post code, street address, GPS waypoint etc). Location awareness is a sensitive privacy consideration for users with a trade off between fears of government or corporate surveillance and access to location specific information. We currently plan to build in two options to UT: Automatic Location Sensing, where the user allows their device to send their position automatically to the UT system to provide instant access to local content and, Manual Location Input, where the user uploads their position directly to the UT system in order to receive local content as and when they choose.
PUBLIC TRIAL: Manual Location Input, or User Declared Location will be the system adopted for the trial.

INTERNET CONNECTION
The user device will communicate with the Urban Tapestries system either through its 802.11 WiFi card or via GPRS or UMTS/3G (such as through a Bluetooth connection to a GPRS or 3G mobile phone). Density restrictions with 802.11 use of the radio spectrum and the current lack of interoperability between WiFi nodes are suggesting that a Mesh/Ad Hoc 802.11 network which enables peering between users will be the most appropriate WiFi solution for the alpha prototype trial.
PUBLIC TRIAL: Proboscis is setting up its own 802.11b Mesh in Bloomsbury using Locustworld's MeshAP for the iPAQ 5450s to connect to. SonyEricsson P800s will connect via the Orange GPRS network.

SERVER ARCHITECTURE
Urban Tapestries will being designed using a server-based component architecture (but not an open API model) responding to data requests from the user device. The server will contain a content database, media files, a location interpreter application, a dynamic map drawing application as well as the main application server handling requests from the client device (XMLRPC) for location specific UT content.
PUBLIC TRIAL: The system architecture has been designed to be scalable to requirements, serving and publishing authored location-based content to and from users, resolving location requests via its GIS map server, and registering users onto the system.