Uplink Interference Coordination In LTE Systems

Interference problem has been the key issue affecting mobile communication, LTE technology is better than the current3G technology to slove intra-cell interference problem, but along with more severe inter-cell interference problem, this makes inter-cell interference suppression technology become the focus in LTE. The air interface used in the uplink is SC-FDMA, SC-FDMA is challenging in terms of channel allocation due to the single carrier property which invokes a constraint that the subchannels allocated to a user have to be adjacent to each other or equally distanced unlike in OFDMA where a user can be assigned subchannels freely. This paper is a study of LTE uplink interference coordination technology, so we must take into consideration the constraints of frequency allocation.At present, the industry presents a variety of inter-cell interference coordination scheme, some of them are based on bandwidth scheduling scheme, and others are based on power control scheme. Although these two solutions can be very good to reduce inter-cell interference, but if we can firstly use the bandwidth scheduling scheme and then use power control scheme, it can be better to reduce inter-cell interference. The main research works of this paper are as follows.(1) According to the uplink bandwidth alloction characteristics, this paper presents a new packet scheduling algorithm. The algorithm by estimating each user in all cell channels’SNR to determine how to allocate channels to the users, the total principle is to allocate channel to the user who has the maximum SNR on it, and also considering the uplink bandwidth alloction characteristics.(2) This paper presents a new uplink interference coordination scheme which combines bandwidth scheduling scheme with power control scheme. The scheme firstly allocates the bandwidth according to bandwidth allocation algorithm, and then allocates appropriate power according to power control algorithm. Experimental results show that after this paper’s bandwidth allocation algorithm to allocate bandwidth, it can be very good to reduce inter-cell interference, together with reasonable power allocation, further reducing inter-cell interference.(3) In the summary of above work, this paper presents a simulation model of LTE uplink interference coordination. Based on the model, compare this paper’s scheme with the existing scheme in throughput, efficiency, time delay and detailed analysis the experimental results.