Research On LTE Uplink Co-Existence Guard Band Utilization Based On Interference Avoidance

Broadband high-speed data communications is the development trend of future wireless communications. Based on the consideration of future development, the Third Generation Partnership (3GPP) launched the "Long Term Evolution" (LTE) process. Based on the technologies of OFDM/MIMO, LTE is characterized by simplified, high spectral efficiency, resistance to multipath fading which captures the attentions of various operators. As the spectrum resource is scarce and full of competitions, according to the 3GPP LTE frequency band planning, it can be figured out that in the foreseeable future, many operators will inevitably deploy their LTE systems in the same geographical area with adjacent frequency bands, which resulting LTE system co-existence interference and degrades system performance. Moreover, the serious OFDM sidelobes leakages aggravate the effect.As co-existence interference causes problems, it is necessary to research on system co-existence and reduces interference. The researchers can guide the deployment in order to reduce co-existence interference; provide hardware requirements indicators; and the same time, contribute to management of spectrum resources, such as setting reasonable guard band and so on.There have been many valuable researches on co-existence, which mainly focus on the issue of "How to reduce co-interference", by formulating geographical layout of the coexistence system to reduce interference and different time slots of interference. Setting guard band in frequency between two systems is also considered as one of the effective strategies to reduce interference; nevertheless, guard band reduces the available spectrum resources.Focus on the guard band issue, this paper sets the goal of reducing coexistence interference and optimizing the overall spectral efficiency, researches the characteristics of co-existence interference, especially the guard band, via theoretical analysis, a strategy utilizing guard band is proposed based on interference avoidance scheme in LTE uplink FDD. The scheme can allocate the appropriate length of resource in guard band to the most appropriate user. The paper models the issue theoretically and simulates the scheme. Simulation results show that guard band resource is full used and at the same time, co-existence interference is also reduced. Focusing on the difficulty of theoretical process, a simplify scheme is introduced, at the cost of a small amount of system performance degradations in comparison to the theoretical values, the complexity of the scheme is substantially reduced.The simulation in the paper refers to the 3GPP LTE system simulation environment, detail steps of the simulation principles are described, the fundamental simulation results are calibrated with 3GPP, which insures the reliabilities of the simulation platform. New schemes are evaluated based on the calibrated platform.