A Downlink and Uplink Alignment Scheme for Power Saving in IEEE 802.16 Protocol

Abstract

This study shows the problem of power saving mechanism (PSM) that sleep intervals of uplink (UL) connections do not synchronize with sleep intervals of downlink (DL) connections. That is, the energy of a mobile station (MS) is not really saved if the DL connections are in the sleep mode while the UL connections are in normal mode, and vice versa. To avoid the asynchronism of power saving (PS) between UL and DL connections, we invent a mechanism of DL connections regulating UL connections, called DL and UL Alignment (DUAL) scheme, to improve the energy efficiency for PS. Considering that the buffer size of MS is limited, DUAL uses the mean packet arrival rate of UL λ u and a relatively safe threshold of buffer size Q T as the parameters to estimate the maximum allowable waiting time to align the UL with the DL connections. To analyze the performance of DUAL, a system model of PS is proposed to evaluate the performance of DUAL under different conditions. The correctness of performance analysis of DUAL is validated by using simulation with realistic parameters. Numerical experiments show that DUAL improves the energy conservation significantly when UL traffic is greater than DL traffic.

An Extra Power Saving Scheme for Prolonging Lifetime of Mobile Handset in the 4G Mobile Networks

“…These types of traffic are lower priority services as compared with GBR services [4] . Because the NRT-VBR services have the delay-tolerant property [15] , they are usually served in a lower priority as compared with real-time (RT) and guaranteed bit rate (GBR) services. This setting will lead to the consequence that NRT-VBR and non-GBR services cannot obtain the bandwidth when they compete with services having higher priority than theirs.…”

Load Sensitive Power Saving Technique for 4G Mobile Network under Limited User Traffic

“…If UL and DL traffic are asynchronous then UL/DL traffic is delayed to make them synchronize with sleep interval. Such concept is applied in [9]; where authors plot the energy consumption against arrival rate of UL and DL. In this paper, limited user traffic model called PCT-II (Pure Chance Traffic II) for a subscriber station (SS) which is sensitive to offered traffic of the user group is dealt with.…”

Gerenciamento energeticamente eficiente de recursos de rádio em redes LTE

“…Para a tecnologia Interoperabilidade Mundial para Acesso de Micro-Ondas (Worldwide Interoperability for Microwave Access, WiMAX), a proposta em [32] alinha as transmissões em downlink e uplink ao entender que o UE não pode entrar no estado ocioso se a interface de rede estiver transmitindo, não importando em qual dos canais. A solução proposta atrasa no UE os pacotes gerados para transmissão em uplink pelo próprio UE antes da chegada à interface de rede até que uma transmissão em downlink tire o dispositivo do modo ocioso.…”

“…Embora em [15] o alinhamento melhore a eficiência energética do UE de forma indireta com a potência de recepção, os modelos de consumo de Lauridsen demonstram que esse efeito no canal downlink é pequeno. Embora os autores de [32] usem o alinhamento para engatilhar o modo ocioso, utiliza-se neste trabalho o tamanho do buffer no UE e os parâmetros de configuração do modo ocioso como restrição para a transmissão em uplink antecipada, sem levar em conta os requerimentos de QoS dos pacotes. O GAPS divide o escalonamento dos recursos em downlink em duas etapas: a de pré-processamento, onde um subconjunto dos bearers em downlink é selecionado para a próxima etapa; e a de alocação de recursos, onde os PRBs são efetivamente distribuídos para o subconjunto dos bearers selecionados na etapa anterior.…”