Title :
Delay constrained optimal power allocation in high-speed railway scenarios
Author :
Chuang Zhang ; Pingyi Fan ; Ke Xiong ; Pingzhi Fan ; Su Yi ; Gang Wang
Author_Institution :
Dept. of Electron. Eng., Tsinghua Univ., Beijing, China
Abstract :
Widespread deployment of high-speed railways in recent years brings huge demands for high-mobility broadband wireless communications. To provide broadband wireless access for passengers in the train, a well acknowledged approach is to apply a two-hop architecture in which users communicate with base stations (BSs) via a mobile relay (MR). Considering quality of service (QoS) requirement of passengers, a crucial issue in this two-hop architecture is how to match user data arrival process and time-varying wireless channel service process with delay constraint at the MR. We deal with this problem from the perspective of power allocation. For constant-rate data arrival and large-scale-fading wireless channel in high-speed railway scenarios, we first present a necessary and sufficient condition for avoiding buffer overflow as well as infinite delay with constant transmit power, and when the transmit power can be adapted, we present the delay constrained optimal power allocation (DCOPA). We find that the proposed DCOPA bridges traditional channel inversion and water filling, which are only suitable for special cases where delay is not allowed and delay is quite loose respectively. Besides, with DCOPA, we present the inherent tradeoff between delay and minimal average transmit power in the system, which provides the optimal operating point for delay constrained traffic at the MR.
Keywords :
delays; fading channels; mobile radio; quality of service; railway communication; relay networks (telecommunication); telecommunication traffic; BS; DCOPA; MR; QoS; base station; buffer overflow avoidance; channel inversion; constant-rate data arrival; delay constrained optimal power allocation; high-mobility broadband wireless access communication; high-speed railway scenario; large-scale-fading wireless channel; mobile relay; quality of service; time-varying wireless channel service processing; two-hop architecture; user data arrival processing; water filling; Channel capacity; Conferences; Delays; Fading; Rail transportation; Resource management; Wireless communication; delay constraint; high-speed railway; mobile relay; power allocation;
Conference_Titel :
Globecom Workshops (GC Wkshps), 2014
DOI :
10.1109/GLOCOMW.2014.7063586