Özet:

The Unlicensed Long Term Evolution (U-LTE) is actually one of the interesting research fields that allows 5GHz unlicensed connectivity, thereby improving the efficiency and reliability of communications. The primary drawback of contributing to these frequency bands is the necessity for co-occurrence with Wi-Fi/IoT devices. This limitation was resolved by the Cognitive Radio Network (CRN) which utilizes the Enhanced Conflict Tolerance (ECT) and Listen-Before-Talk (LBT) schemes to co-occur with U-LTE and Wi-Fi/IoT networks. Nevertheless, it was addressed that the efficiency of scheduled Uplink Transmission (UT) in unlicensed band and the channel access likelihood for the UE were decreased because of the dual LBT requirements at both eNB and User Equipment (UEs). Therefore in this article, a novelUTmechanism in the co-occurrence of U-LTE-Wi-Fi/IoT systems including ECT-LBT is proposedto enhance the UTautonomously based on the Grant-less Multiple Subframe Scheduled Uplink (GMSSUL) transmission. This scheme has the objective of effectively enhancing the efficiency of uplink and downlink together in data transmission.In this scheme, the channel sensing is executed by the UE with uplink data and the fair co-occurrence is preserved by implementing Cat.4 LBT. The UE uses total Highest Channel Possession Time (HCPT) for packet transfer and requires feedback information for Amalgam Automatic Repeat Request (AARQ) process. Further, the uplink subframe is enhanced by proposing Multi-Subframe Scheduling (MSS) that allows multiple channel sensing and simultaneous data transmission. Eventually, the simulation outcomes illustrate the proposed system achieves higher spectral efficiency and throughput than the existing system.

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