Home eNB Research Articles

Design Strategy for Measurement Scheduler in LTE Small Cell-Associated User Equipment

Small cell deployment using Home eNB improves the LTE/LTE Advanced network coverage and capacity providing its relay and data offloading functions. However, latency of inbound mobility to the small cell is a critical obstacle to the deployment because it spends much time detecting an associated small cell due to its sparse deployment and identifying the target small cell because of the delay caused by the verification procedure required before performing inbound handover to the target. Therefore, the inbound handover latency should be minimized to encourage the deployment of the Home eNB. To tackle the handover latency problem, this paper proposes a practically possible solution for design of Layer 1 search/measure scheduler in LTE small cell-associated user equipment. The proposed strategy especially enhances the performance of the LTE Home eNB discovery and guarantees to meet the requirements defined in the corresponding conformance test specifications. Performance evaluation by computer simulation shows that the proposed scheme provides a proper guideline on the Layer 1 software implementation.

Resource Allocation in Two-Tier Heterogeneous Networks through Enhanced Shadow Chasing

This work studies femtocell resource allocation in shared spectrum heterogeneous networks. We propose an enhanced shadow chasing method for femtocell resource allocation to achieve interference mitigation in heterogeneous networks serving both Macrocell User Equipments (MUEs) and Home User Equipments (HUEs). Shadow chasing home eNB (HeNB) uses Downlink Control Information (DCI) together with over-heard macrocell user ACK/NAK feedbacks and CQI reports to assign its own downlink resources to mitigate downlink interference to MUEs. Since the HeNB receives outdated DCI due to backhaul delay, we derive a likelihood metric for each resource unit being either empty or assigned to a (low-interference) outdoor MUE based on a finite-state Markov chain model for each resource unit. By dynamically separating MUE and HUE assignments, the enhanced shadow chasing can better control the downlink interference to MUEs for QoS assurance. It effectively reduces the probability of resource collision and MUE interference compared to schemes not considering backhaul delay effect or user feedbacks.