Spectrum Management - Cross Border

Cross Border coordination

This note describes how ATDI software can be used to meet current needs for cross border spectrum co-ordination in the bands 68MHz to 2500MHz to allow countries to comply with international treaties such as the Vienna 1993 agreement for land borders and the various Memoranda of Understanding such as those existing between Britain and France and Britain and Ireland. The methods and sub-tools within tools such as ICS Telecom have come from our work with various customers. These companies have either used our tools or have contracted ATDI to carry out work on their behalf to further their development of their fixed link networks.

General Cross Border Co-ordination Methods

The following general modelling methods have application in cross border co-ordination and spectrum management in general and are included in ATDI planning tools.

• The ability to compute the coverage of ground area from a given transmitter type and specification to a given receiver type and specification.
• The ability to compute the degree of interference suffered by both mobiles (down link) and base stations (up link) from all emitters on the same or adjacent channels.
• The ability to draw a radio path profile between any two points on the loaded terrain. computing the resulting field strength and showing the Fresnel zone and Fresnel zone fraction and the Earth Radius factor.
• The ability to link the planning tools via a network to allow co-ordination by a number of administrators each with privilege to assign spectrum and agree sharing in their own area of work yet accounting for the effects of those adjacent.
• The ability to link the assignment and co-ordination tools via an Open Data Base Connectivity protocol to external databases such as Oracle and MS Access allowing the sharing of engineering data on assignments across a multi-discipline administration team.
• The counting of area under a transmitter footprint but showing the results over a variety of different urbanisation categories including roads, urban and suburban areas with the addition of an irregular polygon limit.

Specific Cross Border Co-ordination Methods

Using ICS Telecom, the spectrum co-ordinator/administrator can insert proposed sites and base station parameters either from database or directly on screen. He can then compute the resulting field strength for varying percentage of time and locations over differing path types (land, cold sea etc.) and can conclude whether the base station so defined is within the terms of the appropriate agreement or not. In the event of close co-ordination he can then go on to place the victim base stations or mobiles in the adjacent territory and analyse the degree of interference suffered.

In the reverse direction, the co-ordinator can test proposed assignments in adjacent countries and the resulting incoming interference. Clearly also where we talk here of territory and country the same is true between different operators and services in the same area.

The following more specific features are provided:

• The ability to select the terminal, feeder and antenna types from an equipment database. This speeds up site appraisal. Antenna types can be input directly from manufacturers' files or from standard administration masks.
• ICS Telecom uses methods which mirror the Vienna 1993 agreements combining the use of ITU-R curves and diffraction calculations. This assures that co-ordinators meet the letter of the various MOU and use internationally recognised models.
• ICS Telecom also mirrors the methods detailed in CEPT TR20-08 which develops on the methods listed in Vienna 1993 to include over sea and over land paths and which sets limit C/I ratios for the various services.
• Once frequencies are assigned either manually or automatically ICS Telecom can assess the interference to every receiver considering all active transmitters assessing the C/I across the area of interest. Interference assessments can consider both co-channel and adjacent channel (including adj+1 to infinity).
• The ability to view both noise limited and interference limited coverage areas on screen to show the real effect on victim mobiles and base stations.
• The ability to design and view the complete nation-wide plan(s) on screen with base stations and links tagged by their idents and terminal call signs.