XPIC: Cross-Polarization Interference Cancellation (XPIC) Performance In Presence Of Non-linear Effects

Cross Polarization Interference Cancellation (XPIC):

How does Microwave having XPIC capabilities effectively double the potential capacity of a Microwave Path. It allows the assignment of the same frequency to both the vertical & horizontal Polarization on a Path. Where available frequencies are limited then it is possible to assign the same frequency twice on the same path using both Polarizations. SEE MORE AFTER CUT>>>>

Microwave technology, used in main points of mobile backhaul, has now evolved to take advantage of the introduction of Internet Protocol (IP) into the backhaul network to drive higher capacities, increased frequency efficiency, increased flexibility, and optimal cost by combining a number of features to enable true gigabit transport speeds. One of those evolutions regards to the frequency reuse schemas like Co-Channel Dual Polarization (CCDP), which uses two parallel communication channels over the same link with orthogonal polarizations. Due to the nature of these systems, it is inevitable that cross-polar interference occur (e.g. rainfall, multipath, equipments imperfections...), where Cross-Polarization Interference Cancellation (XPIC) technology is adopt as a countermeasure against that interference. However, this cancelation block, normally located at baseband level, process signals that can be affected by non-linear impairments. This paper shows the performance achieved by two XPIC configurations, based on newly introduce XPIC model, in the presence of Saleh model non-linear element, placed at transmitter, for a 256-quadrature amplitude modulation (QAM) signal. CCDP system, which includes XPIC, is simulated using Simulink tool from Mathworks.

Using standard Microwave equipment from any of the major manufacturers, if a full block of eight frequencies were available for a 6 GHz Lower band path then eight frequencies could be assigned in each direction on the path, four per polarization.

Using equipment with XPIC capability, sixteen frequencies may be assigned each way on the same path (eight per polarization).