Nynex Science and Technology, Inc.
Geographic Information Systems Group
Network Planning & Engineering Systems Lab
500 Westchester Ave., White Plains NY 10604
This paper will outline a task model for CSDM in Cellular network management, and present a software environment of existing spatial databases and associated applications that can serve as a starting point for the creation of `cel- lular groupware' for spatial decision-making. While the emphasis is on the problem domain, strategies to create group based spatial decision tools are sug gested as a result of our initial experience.
Almost every facet of building and operating a cellular network depends on a spatial decision process. Planners need to know where, when, and how much subscribers will use their phones so that they can determine how capacity should be distributed across a service area. Marketing departments need to know both where service is offered, and who within that service area is likely to be a potential subscriber. Engineers must model potential network configu- rations to insure that the appropriate signal quality is provided to areas identi- fied by planners. The illustration below is a generalized view of the functional organizations responsible for operating the network, and the primary flow of information among them.
Figure 1 - Organizational Structure
Obviously, the organization encompasses a broad range of spatial decision problems which no single GIS application can support. Individual departments, such as engineering, represent large-scale work environments in their own right. The engineering department at Nynex Mobile has over 200 engi- neers in a number of functional subgroups, located at multiple offices through- out the Northeast. All departments use some type of GIS-based tools in their analysis and reporting.
Individual departments are highly independent, and tend to collect a variety of spatial data on an ad hoc basis. This data is used to produce maps showing the distribution of some feature or the result of an analytical model. Maps are used as a static representation of a feature, to be shown in meetings or included in a report, rather than as a dynamic model of the decision space. The challenge for system designers is to allow decision-makers to make more effective use of spatial data both within and between departments. Within departments, the problem is similar to other large-scale technical project management studies (Grønbæk et al, 1992). This case presents a conventional notion of collaborative work where individuals contribute towards a larger group goal.
To address the use of spatial data between departments is to apply the notion of collaborative work to the exchange of information and ideas among multiple functional groups within an organization. From a social perspective it may be viewed as another case of individuals, in this case department managers, using collaborative methods to solve problems. From the perspective of designing tools that allow participants to exchange ideas in a spatial context, it presents a problem of creating generalized spatial representations of functions conducted by that department. The rest of this paper addresses the current methods used to facilitate interdepartment spatial decision-making.
The core of the environment is the Signal Quality System (SQS), which provides the central database for spatial and network data. SQS is primarily an engineering tool, so it contains highly detailed data on network parameters and activity. SQS is based on a shared database which allows users to access data on the actual state of the network and create their own views of the network. These `cellular views' represent a snapshot of an actual or proposed network configuration, and are made up of both spatial and aspatial data. A cellular view has a multi-layer geographical representation composed of both raster and vector data which are linked to relational data about individual network components. They can be compared to other cellular views, or referenced by external applications for non-engineering purposes.
GIS applications in other departments, such as operations or regulatory, can access a common spatial database as well as cellular views created in SQS by various users. The object of collaboration is now the cellular view, and although the view cannot be edited by multiple users, other applications can derive new data or relate other attributes to it. The multi-layer view can replace a map as the media for exchange of information between departments.
Figure 2 - Spatial Data Analysis Infrastructure
We have tried to leverage the inherent ability of maps as a communication tool to provide a starting point for the development of CSDM support. However, simply providing a map interface does not promote collaborative work. Collaborative tools must promote greater interaction in actual work situations. We have attempted to do this by providing application specific user interfaces, a user-modifiable spatial modeling environment, and easy access to data and applications through a variety of communication protocols.
One obvious weakness in this approach is the lack of support for simultaneous interaction between workers at different sites. Spatial data may be created and viewed by a single user from any location, but there is no capability for a user to modify or suggest changes to another user's data set. A WYSIWIS map editing capability where all users interactively provide input would provide the ideal solution for this purpose. Existing applications also lack strong version- ing procedures to track various stages in the decision process. Multiple cellular views can be created and compared in user workspaces, but no meta-data about these are maintained by the applications. Lastly, the retrieval and processing of spatial data is still slow, and will have to be vastly improved to be useful for interactive decision making capability.
Ellis, C.A., Gibbs, S.J., and Rein, G.L. "Groupware: Some Issues and Experiences", Communications of the ACM, Vol. 34, No. 1, January, 1991. pp. 38-58
Grønbæk, K., Kyng, M., and Mogensen, P. "CSCW challenges in large-scale technical projects - a case study", Proceedings ACM 1992 Conference on Computer-Supported Cooperative Work (1992), ACM Press, pp. 338-345
Greg Theisen is a Member of Technical Staff at Nextwave Communications. He previously worked in the Planning and Engineering Laboratory at Nynex Science and Technology. He has worked on several wireless planning projects, including the Signal Quality System (SQS), a GIS based planning and engineering tool. Current research interests are cellular demand forecasting and wireless technologies.