Yuan Yifei

Ultra Dense Network： Challenges, Enabling Technologies and New Trends

5G sets an ambitious goal of increasing the capacity per area of current 4G network by 1000 fold. Due to the high splitting gain of dense small cells, ultra dense network (UDN) is widely considered as a key component in achieving this goal. In this paper, we outline the main challenges that come with dense cell deployment, including interference, mobility, power consumption and backhaul. Technologies designed to tackle these challenges in long term evolution system (LTE) and their deficiencies in UDN context are also analyzed. To combat these challenges more efficiently, a series of technologies are introduced along with some of our initial research results. Moreover, the trends of user-centric and peer-to-peer design in UDN are also elaborated.

Application scenarios and enabling technologies of 5G

Fast growth of mobile internet and internet-of-things has propelled the concept formation and research on 5G wireless communications systems which are to be standardized around 2020 (IMT-2020). There will be diverse application scenarios expected for 5G networks. Hence, key performance indicators (KPIs) of 5G systems would be very diverse, not just the peak data rate and average/edge spectral efficiency requirements as in previous generations. For each typical scenario, multiple technologies may be used independently or jointly to improve the transmission efficiency, to lower the cost, and to increase the number of connections, etc. Key enabling technologies are discussed which include massive MIMO, ultra-dense deployment specific techniques, nonorthogonal transmission, high frequency communications, etc.