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CDMA Simulation Engine

Whereas traditional simulation of non-CDMA systems is carried out in SEAMCAT by taking two pairs of transmitters-receivers and estimating signals received between them separately (i.e. without any form of feed-back influence), the simulation of CDMA systems requires a much more complex process of power controlling in a fully loaded system, including impact from two tiers of neighbouring cells and, for victim CDMA systems, the attempt by the system to level-out the interference impact.

Therefore SEAMCAT supplements a single considered CDMA cell with its Base Station (BS) two tiers of virtual cells to form a 19 cell (57 cell for tri-sector deployment) cluster, which is then populated with a certain number of mobile stations (MS) and the CDMA power control algorithm is then applied for balancing overall system, see Figure below:

Before the actual simulations start, the CDMAE may run the special algorithm for finding the non-interfered (optimal) capacity of the defined CDMA system. Alternatively, the user may define the load of modelled CDMA system.

Then, in case of CDMA system being the interferer, the CDMAE balances it only once, then notes the transmit powers and positions of relevant transmitters (BS or MS, depending on scenario) and sends them back to EGE as Interfering Transmitters for calculation of iRSS. If the CDMA system is a victim, at first the power balancing is done without the external interferer considered, the achieved in a snapshot number of connected CDMA users (i.e. MSs) noted, and then the external interferer is introduced and CDMA system is re-balanced again. Afterwards the number of served users, compared with that before interference was introduced, allows estimating impact of interference in terms of excess outage brought to the system. Therefore, for CDMA victim, the impact of interference is established through the combined work of EGE and CDMAE modules and does not require subsequent run of ICE.

If both victim and interferer systems are CDMA, then the combination of the above is applied.

Normally the considered CDMA system is modelled as endless network using the so called wrap-around technique. Alternatively, the user may specify that the modelled CDMA cell is laying at the edge of CDMA network, in this case the CDMA system will be modelled as if extending to one side only. The latter case may be suitable for simulation of geographically separated victim and interfering systems, like in cross-border scenarios.

The detailed CDMA power control algorithms implemented in SEAMCAT-3 are described in separate section of this user guide.