Channel Access Acquisition Mechanism Coupled with Cellular Network for Unlicensed Spectrum

Interworking among heterogeneous wireless networks across licensed and unlicensed spectra has gained much attention to support the surge in mobile traffic. Wireless LAN (WLAN) is well known as the dominant wireless network application in the unlicensed spectrum. Unlicensed spectrum access should follow carrier sense multiple access/collision avoidance (CSMA/CA) to share the wireless resource with existing WLAN nodes. However, the transmission throughput with CSMA/CA can be significantly degraded by the hidden terminal problem in environments where huge mobile traffic depletes the wireless resources. In this paper, we propose a channel access acquisition mechanism that uses licensed spectrum access. The proposed mechanism significantly reduces the impact of the hidden terminal problem by using both transmission and reception opportunities. So that the receiver can efficiently get reception opportunities, the information on the user data waiting at the transmitter is notified by using a licensed spectrum channel. Computer simulations show that the proposed access mechanism enables robust transmission even if the wireless resource at the receiver is depleted by transmission from nodes hidden from the transmitter.