臺灣博碩士論文加值系統

近年來，隨著物聯網的蓬勃發展，已經吸引學術界以及產業界的關注。而為了省電，物聯網裝置大部份的時間會處於閒置狀態，有需要收取或是上傳資料才會醒來。現存的協定中，移動性管理組件可以透過呼叫訊息來喚醒在閒置狀態的物聯網裝置。但是透過裝置的辨識碼一對一的方法去喚醒物聯網裝置是非常沒有效率，會佔用太多頻寬。而且一次最多只可以喚醒16個物聯網裝置，當需喚醒的物聯網裝置增加後，會導致嚴重的延遲。因此，此篇論文提出一個新的喚醒方法，在呼叫訊息中，不需要明確的帶有裝置的辨識碼，物聯網裝置只需要檢查是否通過在呼叫訊息中所帶著的過濾器。如果通過過濾器，則代表需要被喚醒起來收取資料；反之，則可以繼續處於閒置狀態。透過模擬分析，我們提出的方法，比傳統的方法減少了高達87\%的訊息大小，並且一個呼叫訊息一次可以喚醒更多處於閒置狀態的物聯網裝置，減少喚醒的延遲時間。

IoT (Internet of Things) is an emerging network paradigm connecting a huge number of things. For energy saving, small things (sensors) usually stay in the idle mode and only wake up when they have traffic demands. In traditional LTE, the MME invokes UEs by notifying them via a paging message including a list of their IDs. However, such one-by-one notification will incur an unacceptable signaling overhead in an IoT network when the ID list is long. To address this issue, this work presents “page by hint” (p-Hint), an ID-free paging mechanism that allows the MME to page a large number of UEs using only a fixed-length hint. The key idea of p-Hint is to leverage hashing to encode and decode the hint message. In this thesis, we design two schemes for different scenario. Two schemes are based on simple hashing processes with one or multiple bit-vectors as filter. One is single-filter scheme while the other is dual-filter scheme. Through these filters, each UE checks whether its information is contained in the hint message via same hashing processes, and determines whether it should get up to do random access. To improve spectrum efficiency, we further mathematically derive the optimal length of the hint so as to maximize the expected number of UEs that can be successfully paged per unit
of overhead. The simulation results show that p-Hint can page much more UEs simultaneously in a single paging procedure. As compared to legacy LTE-A, single-filter scheme reduces the overhead of successfully paging one UE, on average, by 85.7%, while dual-filter scheme reduces the overhead, on average, by 90.1%. We also observe that the average overhead required for successfully paging one UE in no more than 25 bits for single-filter scheme, and no more than 11 bits for dual-filter scheme, which both are much smaller than the size of UE ID (40-bit
S-TMSI).

摘要i
Abstract ii
誌謝iii
Contents iv
List of Figures vi
List of Tables vii
1 Introduction 1
2 Background 3
2.1 Bloom Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Paging in LTE-A and NB-IoT . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.3 Related Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3 Design of p-Hint 6
3.1 Problem Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.2 Paging Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4 Single-Filter and Dual-Filter Hint Scheme 10
4.1 Single-Filter Hint Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2 Dual-Filter Hint Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5 Analysis Of Optimal Hint Length 14
5.1 Analysis for Single-Filter Hint Scheme . . . . . . . . . . . . . . . . . . . . . . 14
5.2 Analysis for Single-Filter Hint Scheme . . . . . . . . . . . . . . . . . . . . . . 15
6 Performance Evaluation 18
6.1 Impact of the Mask Length in Single-Filter Scheme . . . . . . . . . . . . . . . 18
6.2 Impact of the Bloom Filter Length and Mask Length in Dual-Filter Scheme . . 19
6.3 Impact of Number of Multiple Hash for Bloom Filter in Dual-Filter Scheme . . 20
6.4 Comparison between Single-Filter Scheme and Dual-Filter Scheme . . . . . . 21
6.5 Paging Overhead . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
6.6 Scalability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
6.7 Paging Latency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
7 Conclusions 26
Bibliography 27

[1] Y. Shi, W. Xi, and H. Zhou, “Efficient paging message design based on binary tree in NB-IoT system,” in Proc. IEEE CSCN, 2016.
[2] D. Evans, “The internet of things: How the next evolution of the internet is changing everything,” CISCO white paper, Apr. 2011.
[3] 3GPP RP 1511621 (Sep. 2015), Narrow Band IoT (NB-IoT), Std.
[4] 3GPP TS 36.304 V14.2.0 (Mar. 2017), 3GPP User Equipment (UE) procedures in idle mode, Std.
[5] 3GPP TS 36.331 V14.1.0 (Jan. 2017), LTE RRC Protocol specification, Std.
[6] 3GPP TS 23.003 V14.3.0 (Mar. 2017), 3GPP Numbering, addressing and identification, Std.
[7] C.-H. Wei, R.-G. Cheng, and S.-L. Tsao, “Performance analysis of group paging for machine-type communications in LTE networks,” IEEE Transactions on Vehicular Technology, vol. 62, no. 7, pp. 3371–3382, 2013.
[8] O. Arouk, A. Ksentini, and T. Taleb, “Group paging-based energy saving for massive MTC accesses in LTE and beyond networks,” IEEE Journal on Selected Areas in Communications, vol. 34, no. 5, pp. 1086–1102, 2016.
[9] B. H. Bloom, “Space/time trade-offs in hash coding with allowable errors,” Communications of the ACM, 1970.
[10] T. Ta and J. S. Baras, “Enhancing privacy in lte paging system using physical layer identification,”
in Data Privacy Management and Autonomous Spontaneous Security. Springer, 2013.
[11] R. P. Brent, “Some efficient algorithms for solving systems of nonlinear equations,” SIAM Journal on Numerical Analysis, vol. 10, no. 2, pp. 327–344, 1973.