SURs - Verification Approaches

Statement

Executive Summary

Context of this Statement

1.1 In December 2007 we published a statement on Spectrum Usage Rights (SURs) which set out modelling as our proposed approach to verify licensees’ compliance with SUR licence terms. In that statement we provided an example of how such verification might work but indicated that other cases would need further consideration.

1.2 In January 2008 we published a consultation setting out the additional cases needed along with a proposed approach to each and inviting input as to whether the approaches were appropriate. Following from the responses, we held a number of stakeholder workshops to ensure we fully understood the issues raised by respondents and to collaboratively explore alternatives. Having done so, we are now able to issue this statement.

1.3 This Statement sets out the general outlines of the approach to be adopted where compliance with SUR terms is to be verified. We anticipate that in each particular case, for example each auction where SURs are adopted, that more specific details will be provided, for example including the propagation model to be adopted and precise details on the parameters and process to be used.

Types of modelling needed

1.4 We believe that the types of modelling needed are:

• From one downlink to another adjacent downlink.
• From one uplink to another adjacent uplink.
• From one downlink to an adjacent uplink.
• From one uplink to an adjacent downlink.

1.5 We believe that combinations of these cases can cover situations such as the use of Time Division Duplex (TDD) technology.

1.6 The first of these cases were set out in the SUR statement and is repeated in this statement for ease of reference. The other cases are discussed in this statement.

Uplink to adjacent uplink

1.7 In outline, the approach is to determine for each cell in the test area a representative number of mobiles in the cell and then assign to each a transmit power based on their distance from the base station. The approximate coverage area of the cell is then determined and mobiles distributed evenly across the cell. The total interference from all mobiles to each test point in the measurement area can then be determined using the same propagation model as adopted for the downlink to downlink interference case.

Downlink to adjacent uplink

1.8 In outline, in this case the approach is to sum the interference from each of an operator’s base stations at each test point across the measurement area. Both the transmitter and receiver are assumed to be at heights typical for base stations.

Uplink to adjacent downlink

1.9 In outline, in this case the approach is to model the interference occurring at each test point within the test area. This modelling is based on assessing the density and average power of mobiles within the test point and determining the interference caused to multiple points throughout the test area using transmitter and receiver heights typical for mobiles. In practice, a simple formula can be provided such that if the density and average powers are known the interference can be quickly determined without needed to perform modelling.

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