Service- and interference-aware dynamic TDD design in 5G ultra-dense network scenario

Abstract

The 5G wireless communication system supports varied applications, making the uplink/downlink traffic asymmetry more and more serious. Dynamic time division duplex (TDD) technique has become a key technology of 5G networks due to its flexibility to support asymmetric services. In this paper, we study dynamic TDD sub-frame reconfiguration algorithm based on shifting. Firstly, we define cell shifting priority considering both traffic and interference. Then, we perform cell shifting-based TDD sub-frame reconfiguration following cell shifting priority. Simulation results show that the proposed dynamic TDD algorithm can guarantee high data rate and low interference, thus effectively increases the network throughput.

Joint power allocation and subcarrier assignment for device to device in 5G time division duplex networks

“…Constraint (9) ensures that one CUs' frequency subcarriers can be shared at most by one D2D pair, but one D2D pair can reuse multiple CUs' frequency subcarriers. Constraint (10) shows that if D2D pair cannot occupy the subcarrier, then the power allocated on subcarrier is zero. Clearly, P1 is a MINLP problem.…”

“…Since the D2D throughput strongly depends on the number of D2D pairs, we evaluate the impact of the number of D2D pairs on the performance of D2D throughput and D2D admission rate in Figures 8 and 9, respectively. We set the number of CUs to be 60 and the fraction time for UL to be 0.5, then vary the number of D2D pairs in the range of [10,60]. It can be seen from Figure 8 that the throughput of D2D increases as the number of D2D is increased for all schemes.…”

“…9 So time division duplex (TDD) systems play an important role in 5G networks due to its capability to support asymmetric services by adjusting the fraction of time dedicated to UL and DL transmissions as well as reduce signaling and radio frequency front-end complexity by exploiting channel reciprocity. 10,11 In addition, D2D communication and TDD system have the same characteristics that each transmitter–receiver pair has the freedom to schedule its time and frequency resources, which not only can minimize the interference between simultaneously transmitting radio entities but also support diverse services.…”