Analytical evaluation of extended DRX with additional active cycles for light traffic

Abstract

LTE and LTE-Advanced mobile technologies have integrated discontinuous reception (DRX) power saving method to optimize the power consumption at the user equipment (UE). The DRX method was proposed by the 3rd Generation partnership Project (3GPP), and since then, the traffic behavior has been analyzed in several studies with a standard 3-state DRX model to describe the trade-off between power saving and delay. In this paper, we presented a novel 4-state and 5-state 3GPP LTE DRX mechanisms. The proposed mechanisms were developed by augmenting (an) active state(s) to deep and/or light sleep cycle of standard 3-state DRX for handling a small burst of packets, thereby bypassing the process of returning to the timer-dependent active mode. We have generated analytical models using a semi-Markov process for bursty packet data traffic and evaluated these augmented DRX mechanisms against a standard 3-state DRX method. Overall, the analytical results from varying timing parameters showed that our augmented DRX (both 4-state and 5-state) improved power saving factor (ranging between 1% and 8%) and reduced delay (ranging between 20% and 60%) compared to the standard 3-state DRX. Furthermore, the magnitude of improvement for both delay and power-saving was somewhat greater in 5-state than 4-state.

Extended hybrid directional DRX with auxiliary active cycles for light traffic in 5G networks

“…After the document is successfully received by the terminal, the user spends some time to study the information, constituting the reading time, which is the interpacket call idle time in the ETSI traffic model . The parameters and distributions of the ETSI traffic model are given in Table …”

“…However, the data exchange can be small with short packet bursts for social networking applications, synchronization messages, UE update messages, etc. In the former case, the traffic can be considered as heavy and the latter as light . In both cases, on the arrival of a packet in short or long sleep period, the UE has to move to the active state and DRX process starts from the beginning.…”

“…A new incoming packet call may be the part of an ongoing session or it can be the first packet call of the next session. Therefore, the interarrival time between two packet calls may be the interpacket call idle time with probability P pc = 1–1/μ pc or the intersession idle time with probability P s = 1/μ pc …”

“…If the semi‐Markov process is viewed only at the time of state transitions, an embedded Markov chain is obtained with the state transition probabilities P ij , where i, j ∈ {1,2,3,4,5,6} …”

“…Discontinuous reception (DRX) has been used as an efficient power saving protocol at the UE in various standards like Universal Mobile Telecommunications System (UMTS), Long‐Term Evolution (LTE), and Long‐Term Evolution Advanced (LTE‐A) wireless networks . In DRX mechanism, the incoming packets are received in a discontinuous manner at the UE instead of the packets being continuously sensed and received in earlier wireless standards.…”