在寬頻無線存取網路中，當行動裝置沒有在傳送及接收資料時，其可進入睡眠模式以節省電量。IEEE 802.16e標準已根據睡眠模式運作方式定義了三種節能的模式。然而，當行動裝置具有多個連線且在連線中沒有一致的睡眠時間時，節能效率會不太理想。本論文提出一個睡眠傾聽交錯的演算法(Interleaved-Sleep-Listen, ISL)。ISL利用交錯的排程來同步連線之睡眠時間，藉以獲得最大未使用時間區間（Maximum Unavailable Interval, MUI）。模擬的結果顯示ISL提升了在多個連線情況下之節能有效性。
睡眠/傾聽時間必須藉由基地台(Base Station, BS)來安排至正交分頻多工（Orthogonal Frequency Division Multiplexing, OFDM）的訊框裡。如果在無線電資源不夠的情況下，BS將無法充分的分配OFDM時槽給MS來傳送封包資料。因此本論文進一步提出一個稱之為睡眠傾聽交錯碰撞避免的演算法(Interleaved-Sleep-Listen with Collision Avoidance, ISL/CA)。此方法可同時解決資源分配與節能有效性的問題。ISL/CA藉以分配較後的OFDM時槽，以滿足頻寬請求大於訊框容量之封包，並且運用交錯的排程方式達到同步之睡眠時間，以降低行動裝置的耗電量。模擬的結果顯示相較於之前的方法，ISL/CA在多連線的情況下具有較好的產能且改進節能的有效性。

In broadband wireless access (BWA) networks, the power consumption of the mobile devices can be saved by allowing the nodes to enter the sleep mode when they are not transmitting or receiving data. IEEE 802.16e standard has defined three power-saving classes (PSCs) according to the sleep modes. However, the power-saving efficiency is not acceptable because the sleep windows of multiple connections are not overlapping when these connections coexist in a mobile station (MS). Therefore, this dissertation proposes an Interleaved-Sleep-Listen (ISL) algorithm, which synchronizes the overlapping sleep windows with interleaving scheduling to obtain the maximum unavailability interval (MUI). The simulation results show that ISL improves the power-saving efficiency under the condition of multiple connections existing in a MS.
The sleep/listen windows must be scheduled by the base station (BS) in unit of an Orthogonal Frequency Division Multiplexing (OFDM) frame. If the radio resources are insufficient, the BS can not allocate enough slots for the packets that should be transmitted in an OFDM frame to a MS. Therefore, this dissertation further proposes a method - Interleaved-Sleep-Listen with Collision Avoidance (ISL/CA) algorithm. This method addresses both resource allocation and power-saving efficiency in IEEE 802.16e networks. ISL/CA allocates latter OFDM slots to satisfy the packets whose required bandwidth is larger than the capacity of an OFDM frame and synchronizes the overlapping sleep windows with interleaving scheduling to reduce the power consumption of the mobile station. Simulation results show that the superior performance of ISL/CA and improves the power-saving efficiency, compared with the previous algorithms, in the condition of multiple connections existing in a MS.

[1].IEEE, “IEEE standard for local and metropolitan area networks part 16:
air interface for fixed broadband wireless access systems,” IEEE
Standard, Dec. 2001.
[2].IEEE, “IEEE standard for local and metropolitan area network part 16: air
interface for fixed broadband wireless access systems,” IEEE Standard,
Oct. 2004.
[3].IEEE, “IEEE standard for local and metropolitan area networks part 16:
air interface for fixed and mobile broadband wireless access systems,
amendment 2: physical and medium access control layers for combined fixed
and mobile operation in licensed bands and corrigendum1,” IEEE Standard
802.16e-2005.
[4].S.-L. Tsao and Y.-L. Chen, “Energy-efficient packet scheduling algorithm
for real-time communications in a mobile WiMAX system,” IEEE Computer
Communications, pp. 2350-2359, 2008.
[5].S.-C. Huang, R.-H. Jan, and C. Chen, “Energy efficient scheduling with
QoS guarantee for IEEE 802.16e broadband wireless access networks,” IEEE
International Conference on Wireless Communications and Mobile Computing,
pp. 547-552, 2007.
[6].T.-C. Chen, Y.-Y. Chen, and J.-C Chen, “Maximizing unavailability
interval for energy saving in IEEE 802.16e wireless MANs,” IEEE
Transactions on Mobile Computing, vol. 8, no. 4, pp. 475-487, Apr. 2009.
[7].C. Ding, D. Pei, and A. Salomaa, Chinese remainder theorem-applications in
computing, coding, cryptography, World Scientific, 1996.
[8].I. Niven, H.S. Zuckerman, and H.L. Montgomery, The theory of numbers, John
Wiley & Sons, 1991.
[9].Y. Xiao, “Energy saving mechanism in the IEEE 802.16e wireless MAN,”
IEEE Communications Letters, vol. 9, no. 7, pp. 595-597, July 2005.
[10].Y. Zhang and M. Fujise, “Energy management in the IEEE 802.16e MAC,”
IEEE Communications Letters, vol. 10, no. 4, pp. 311-313, Apr. 2006.
[11].M.-G. Kim, J.-Y. Choi, and M. Kang, “Adaptive power-saving mechanism
considering the request period of each initiation of awakening in the
IEEE 802.16e system,” IEEE Communications Letters, vol. 12, no. 2, pp.
106-108, Feb. 2008.
[12].D.T.T. Nga, M.-G. Kim, and M. Kang, “A novel energy saving algorithm
with frame response delay constraint in IEEE 802.16e,” IEEE Transactions
on Communications, vol. E91-B, no. 4, pp. 1190-1193, Apr. 2008.
[13].D.T.T. Nga, M.-G. Kim, and M. Kang, “Delay-guaranteed energy saving
algorithm for the delay-sensitive applications in IEEE 802.16e systems,”
IEEE Transaction on Consumer Electronics, vol. 53, no. 4, pp. 1339-1347,
Nov. 2007.
[14].M.-G. Kim, J.-Y. Choi, and M. Kang, “Adaptive power management mechanism
considering remaining energy in IEEE 802.16e,” IEEE Transactions on
Communications, vol. e90-b, no. 9, pp. 2621-2624, Sep. 2007.
[15].H.-L. Tseng, Y.-P. Hsu, C.-H. Hsu, P.-H. Tseng, and K.-T. Feng, “A
maximal power-conserving scheduling algorithm for broadband wireless
networks,” IEEE Wireless Communications and Networking Conference, pp.
1877-1882, 2008.
[16].J.-J. Chen, J.-M. Liang, and Y.-C. Tseng, “An Energy Efficient Sleep
Scheduling Considering QoS Diversity for IEEE 802.16e Wireless
Networks,” IEEE International Conference on Communications, 2010.
[17].L. Tian, Y. Yang, J. Shi, E. Dutkiewicz, and G. Fang, “Energy efficient
integrated scheduling of unicast and multicast traffic in 802.16 WMANs,”
IEEE Global Telecommunications Conference, 2007.
[18].T.-C. Chen and J.-C Chen, “Extended maximizing unavailability interval
(eMUI)：maximizing energy saving in IEEE 802.16e for mixing type I and
　　 type II PSCs,” IEEE Communications Letters, vol. 13, no. 2, pp. 151-153,
　　 Feb. 2009.
[19].K. Han and S. Choi, “Performance analysis of sleep mode operation in
IEEE 802.16e mobile broadband wireless access systems,” IEEE Vehicular
Technology Conference, vol. 3, pp. 1141-1145, 2006.