In an ultra-dense network (UDN) where there are more base stations (BSs) than active users, it is possible that many BSs are instantaneously left idle. Thus, how to utilize these dormant BSs by means of cooperative transmission is an interesting question. In this paper, we investigate the performance of a UDN with two types of cooperation schemes: Non-coherent joint transmission (JT) without channel state information (CSI) and coherent JT with full CSI knowledge. We consider a bounded dual-slope path loss model to describe UDN environments where a user has several BSs in the near-field and the rest in the far-field. Numerical results show that non-coherent JT cannot improve the user spectral efficiency (SE) due to the simultaneous increment in signal and interference powers. For coherent JT, the achievable SE gain depends on the range of near-field, the relative densities of BSs and users, and the CSI accuracy. Finally, we assess the energy efficiency (EE) of cooperation in UDN. Despite costing extra energy consumption, cooperation can still improve EE under certain conditions.
|Title of host publication||EuCNC 2017 - European Conference on Networks and Communications|
|Publisher||Institute of Electrical and Electronics Engineers Inc.|
|Publication status||Published - 2017 Jul 13|
|Event||2017 European Conference on Networks and Communications, EuCNC 2017 - Oulu, Finland|
Duration: 2017 Jun 12 → 2017 Jun 15
|Name||EuCNC 2017 - European Conference on Networks and Communications|
|Other||2017 European Conference on Networks and Communications, EuCNC 2017|
|Period||17/6/12 → 17/6/15|
Bibliographical noteFunding Information:
ACKNOWLEDGMENT This research has been partly supported by the H2020 project METIS-II co-funded by the EU. The views expressed are those of the authors and do not necessarily represent the project. It was also supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (NRF-2015K2A3A1000189).
All Science Journal Classification (ASJC) codes
- Computer Networks and Communications
- Hardware and Architecture