Improvement of LTE system performance by reducing changes of inter-cell interference levels

Interference is one of the most performance-limiting factors in wireless communications systems. The standard of 3GPP Long Term Evolution (LTE) employs Orthogonal Frequency Division Multiple Access (OFDMA) in the downlink, where orthogonality between different users within one cell can be guaranteed by scheduling simultaneously in frequency and time domain. However, LTE is designed to consider a frequency reuse factor of one between adjacent cells leading to strong inter-cell-interference between adjacent cells.
Users especially located at cell edges may experience strong interference by transmissions from neighboring cells, scheduling their users at the same physical resource. Thus, intercell interference coordination (ICIC) techniques are an indispensable and widely discussed topic in the standardization process of LTE.
Scientists at the Department of Communications Engineering at the University of Bremen developed a coordination scheme to improve the reallocation procedure of succeeding pre-coding matrices, while avoiding sudden change in the inter-cell interference experienced at neighboring cells. To do so, they use the fact that different matrix combinations exhibit lower variations in the inter-cell-interference than others. The advantage of this approach is that the variation of the interference level is only determined by the two pre-coding matrices of the allocation, and not by further network, mobile devices or transmission specific parameters
This will lead to significant improvement on system performance on mobile devices to an edge of a cell or located next to base stations as well of base stations without impact on LTE standard. Besides, network stability is also improved.
Up to now, simulations of the computer-implemented method are successful.

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