Research on utilizing guard band in LTE uplink co-existence based on uncoordinated deployment scenario

In order to reduce the impact of adjacent channel interference (AG) to other licensed system deploying at the adjacent channel, nearly 10% of the system bandwidth at the edge of the transmitted bandwidth is reserved as guard band. Generally, transmitting on guard band increases data rate for one system but the followed ACI decreases another system deploying adjacently in frequency, which might decrease the overall spectrum efficiency for those two co-exist systems. However, in some cases for the uncoordinatedly deployed co-existence (the base stations of the two systems do not deploy co-site), transmitting on guard band in LTE uplink for one system increases data rate and only causes minor ACI to the adjacent system. To make full use of guard band and simultaneously make the ACI controllable, this paper proposed a novel scheme of utilizing the guard band in LTE uplink, named Available Bandwidth Determination (ABWD) in guard band. The scheme tries to optimize the overall spectrum efficiency of the two systems adjacently deployed on frequency. Simulation results show that utilizing guard band brings more a data rate gain than loss and more gain would derive via ABWD.