Article Contents
Article Contents

# Selection of DRX scheme for voice traffic in LTE-A networks: Markov modeling and performance analysis

• * Corresponding author: Selvamuthu Dharmaraja
• Power saving is a leading issue in the User Equipment (UE) for limited source of power in Long Term Evolution-Advanced (LTE-A) networks. Battery power of an UE gets exhaust quickly due to the heavy use of many service applications and large data transmission. Discontinuous reception (DRX) is a mechanism used for power saving in UE in the LTE-A networks. There are scope of improvements in conventional DRX scheme in LTE-A networks for voice communication. In this paper, a DRX scheme is chosen by selecting optimal parameters of DRX scheme, while keeping Quality of Service (QoS) delay requirements. Further, delay analysis for first downlink packet is performed. Moreover, expressions for delay distribution and expected delay of any downlink packet, are obtained and represented graphically. Based on analytical model, the trade-off relationship between the power saving and queueing delay is investigated.

Mathematics Subject Classification: Primary: 68M20; Secondary: 60K25.

 Citation:

• Figure 1.  Basic structure of DRX scheme

Figure 2.  One-way communication ON-OFF model for voice traffic

Figure 3.  State transition diagram for two-way communication

Figure 4.  Packet arrival in one-way communication voice traffic

Figure 5.  Frame structure and DRX cycle in LTE-A networks

Figure 6.  When sleep period is terminated by a packet

Figure 7.  Trade-off between expected delay and time

Table 1.  List of transition rates per second

 $\alpha_{1,4}$ $\alpha_{1,7}$ $\alpha_{3,1}$ $\alpha_{2,1}$ $\alpha_{7,1}$ $\alpha_{4,1}$ $\alpha_{5,1}$ $\alpha_{1,2}$, $\alpha_{7,2}$ $\alpha_{6,5}$ $\alpha_{6,8}$ $\alpha_{2,6}$ $\alpha_{3,6}$ $\alpha_{8,6}$ $\alpha_{5,6}$ $\alpha_{4,6}$ $\alpha_{6,3}$, $\alpha_{8,3}$ $0.833$ $5.489$ $2.157$ $2.324$ $27.62$ $2.222$ $1.044$ $~0.278$

Table 2.  Parameters in DRX Scheme

 Parameters Details Half frame Duration (ms) $5$ Duplexing TDD cDRX ON duration timer (ms) $1$ DRX inactivity timer period (ms) $0-100$ Short DRX cycle length (ms) $20$ Long DRX cycle length (ms) $40-100$ Average silence period (ms) (in one-way communication) $650$ Average talking period (ms)(in one-way communication) $350$ Power consumption in awake mode (mJ/ms) $0.24$ Power consumption in sleep mode (mJ/ms) $0.02$ Additional energy consumption(${\mu}J$) $0.2$

Table 3.  Number of sleep cycles exhausted in state $S_i$

 $\tau_{1}$ $\tau_{2}$ $\tau_{4}$ $\tau_{7}$ $\tau_{6}$ $\tau_{3}$ $\tau_{5}$ $\tau_{8}$ $7$ $11$ $6$ $0$

Table 4.  Limiting probabilities

 $\pi_{1}$ $\pi_{2}$ $\pi_{4}$ $\pi_{7}$ $\pi_{6}$ $\pi_{3}$ $\pi_{5}$ $\pi_{8}$ $0.3289$ $0.0236$ $0.0839$ $0.06472$

Table 5.  Power saving percentage comparison for DRX scheme in one-way and two-way voice

 Length of Long DRX cycle(ms) One-way $P_{0}$$(\%) Two-way P_{L}$$~(\%)$ $40$ $81.96$ $74.78$ $60$ $84.31$ $75.0041$ $80$ $85.75$ $75.12$ $100$ $86.72$ $75.19$

Figures(7)

Tables(5)