A Position Approach Based on the Special Sub-frame in TDD LTE-A System

With the urgent need for indoor and outdoor seamless navigation service, it is imperative to develop high precise positing technique suitable for various scenarios. In this paper, considering the widely deployment and well coverage of the wireless cellular communication system, a position approach is proposed based on time duplex division long term evolution advanced (TDD LTE-A) network. A novel complex frame structure for positing is proposed based on the current TDD LTE-A protocol. In GP (Guard Period) of the special sub-frame, i.e., the downlink-uplink switch period of TDD system, the navigation (NV) signal is added for positing. NV signals are transmitted simultaneously from different base station (BS) with orthogonal PN (Pseudo Noise) code. By measuring the distance to different BSs which are time synchronized in TDD system, user's position can be fixed as in the GNSS system. In this paper, the theoretical performance of the proposed position scheme will be analyzed, and the impact to the current system will also be discussed. The results show that, by properly allocating the time length of NV signal based on the coverage of the cell, signal conflicts with the current LTE-A signal can be effectively avoided.