Signaling Overhead and Power Consumption during Handover in LTE

Abstract

In this paper, we address the signaling overhead and the power consumption that results from the transmission of handover-related signaling in a Long Term Evolution (LTE) cellular network. Specifically, we analyze the contribution of the different signaling messages over the air-interface, and their impact on power consumption both at the eNB and at the User Equipment (UE) during handover (HO). A quantitative analysis is provided using system level simulations. We observe that, within the HO process, the largest contributor to air-interface signaling overhead is the transmission of the measurement report by the UE. This uplink (UL) transmission suffers from different channel impairments, due to interference and transmission range, for particular cell sizes. As a consequence, uplink signaling retransmissions are triggered causing higher signaling load and consequently higher power consumption, this being especially detrimental to battery-powered devices.

Receiver Power Consumption during Handover in LTE

“…Now we can find the number of information bits per TB ( ) using [13], which includes 128 bits for the MeasReport Rx and 24 CRC bits. Now, the time-averaged supply power can be written as using [6], (8) where we have defined as the signaling rate which will be obtained from system level simulations.…”

“…We apply well-known power consumption models for both the eNB and UE, [2][4], to obtain the received power necessary to receive the data for each of the signaling messages. In particular, the supply power for the eNB signaling reception, , can be written as (6) where is the received power given by (5) and is the power amplifier efficiency. Equally, the supply power for the UE to receive signaling message , , is given by…”

“…In our previous work [5], we showed the impact of varying the inter-site distance (ISD), User Equipment (UE) speed and HO related parameters on the HO performance parameters and we found that increasing/decreasing the cell size, after a certain limit, degrades the HO performance mainly due to the uplink (UL) limitations. In [6], we analyzed the signaling overheads and the power consumption during the transmission of HO related signaling messages. We found that the measurement report (MeasReport) transmission is the major contributor to the airinterface signaling.…”

Uplink Reference Signals for Energy-Efficient Handover

“…In our previous work [19], we found that increasing/decreasing the inter-site distance (ISD), after a certain limit, degrades the HO performance mainly due to limitations in the UL. In [20], we included a power consumption model for the transmitted signaling messages during handover. We showed that, although the measurement report (MeasReport) transmission is the major contributor to the air-interface signaling, random access channel (RACH) transmission is the main power consuming contributor due to its higher utilization of the resources (i.e.…”

A Simulation Study on Handover in LTE Ultra-Small Cell Deployment: A 5G Challenge

“…Otherwise, the capacity gain achieved through densification will be counter-balanced with an increased number of HOs since the signaling overheads produced during the HO procedure reduces the user throughput [2]. The frequent HOs with ping-pong (PP) effect and HO failures also result in higher power consumption both at the network and user equipment (UE) side that further leads to high CO2 emissions [3]. In addition, if a high speed user goes through multiple HOs, the cumulative HO latency will result in a severe deterioration of the user QoE [4].…”