Abstract—To handle the huge traffic in cellular networks and increase the offered bandwidth for User Equipment (UE), we proposed two enhanced methods to simultaneously access the channels in Heterogeneous Bands (HetBands). The Enhanced Dual Band Femtocell (EDBF) is utilized in single Radio Access Technology (RAT) that comprises Long Term Evolution (LTE) only, while Enhanced Integrated Femto Wi-Fi (EIFW) cell can be used for multi-RAT network (LTE and Wi-Fi). Using the unlicensed band as a supplementary band that usually occupied by Wi-Fi devices (wDevices), a fair sharing can be achieved, and however it may result in reduced network throughput. This work proposes a novel framework to enhance the overall Base Station (BS) performance of both methods in unlicensed band, thus attaining optimal throughput and fair sharing. Firstly, we proposed a channel access scheme for each enhanced method adopts our new procedure that effectively use the scheme parameters (T_attempt, T_trans, and T_sense) to enhance the BS performance. Secondly, two new approaches are proposed in our analytic model to obtain the channel and manage coexistence in unlicensed band based on the channel states and scheme's parameters. Thirdly, a new formulation is proposed in our dynamic algorithm to obtain the optimal fraction of channel time in unlicensed band (t_f^*), using the optimal power in licensed band (P_f^*(s)). We validated our analysis in terms of fair sharing using simulation. Results show that our proposed framework substantially enhance the overall performance of both enhanced methods in terms of throughput, fraction of channel sharing time, and traffic balancing, which make EDBF and EIFW attractive small cells to be used (one type or both) in the deployments of current and future cellular networks.

Index Terms—Aggregation technologies, channel access scheme, dual band femtocell, heterogeneous bands, integrated femto Wi-Fi, listen-before-talk technique

Cite: Saif Hikmat Mousa, Mahamod Ismail, Rosdiadee Nordin, and Nor Fadzilah Abdullah, "Enhanced Channels Access Methods in HetBands for Single and Multi-RAT Femtocell Networks," Journal of Communications vol. 15, no. 12, pp. 849-865, December 2020. Doi: 10.12720/jcm.15.12.849-865

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