An experimental test bed for the evaluation of the hidden terminal problems on the IEEE standard

Transcription

1 ITU Kaleidoscope 2014 Living in a converged world - impossible without standards? An experimental test bed for the evaluation of the hidden terminal problems on the IEEE standard David Rodenas-Herraiz, Antonio-Javier Garcia-Sanchez, Felipe Garcia-Sanchez and Joan Garcia-Haro Department of Information and Communications Technologies Universidad Politecnica de Cartagena (Spain) 1

2 Summary Motivation IEEE Mesh Network Forma0on Asynchronous Energy Saving Mode Architecture and Implementation Performance Evaluation 2

3 Motivation Wireless Mesh Sensor Networks (WMSNs) Destination Wireless Sensor Network (WSN) Wireless Mesh Sensor Network (WMSN) Wireless sensor platform: TelosB device provided by MEMSIC Inc. Source Mesh capability Link Scalability Energy reliability efficiency Self-organization Interoperability Robustness Security Multi-hop mesh routing 3

4 Motivation Wireless Mesh Sensor Networks (WMSNs) 216 surveyed industrial automation professionals and end users (%) 75% have installed or planed a Wireless Sensor Network 75% consider employing IEEE based WSNs including mesh capability 20% intend to exclusively use Wireless Mesh Sensor Network solutions Fig Trend shown by the industrial automation market in the last few years. On World (Hatler et al., 2012) By 2016, 39% applications and services will be uniquely enabled by Low-Rate Wireless Personal Area Mesh Networks (LR-WPAN Mesh) (Hatler et al., 2012) 4

5 Motivation Wireless Mesh Sensor Networks (WMSNs) Smart Santander City Up to nodes deployed in Santander (Spain) to create a Smart City 5

6 Motivation Wireless Mesh Sensor Networks (WMSNs) GreenOrbs More than 1000 nodes deployed in TianMu Mountain, Zhejiang (China), for long-term ecological surveillance 6

7 Motivation Wireless Mesh Sensor Networks (WMSNs) 7

8 Motivation Wireless Mesh Sensor Networks (WMSNs) Feature Multi-hop mesh routing ü û NA NA û û ü Scalability û û NA NA ü ü ü Energy efficiency û û û ü ü ü ü Link reliability û û NA ü û ü ü End-to-end reliability û û NA NA ü ü û Robustness û û NA ü ü ü û Interoperability ü ü ü ü û û ü Self-organization ü ü ü ü ü ü ü Security ü û NA NA ü ü NA Mobility support ü ü NA û ü ü ü 8

9 Motivation Wireless Mesh Sensor Networks (WMSNs) Decisions Use of IPv6 û ü ü Compatible û ü Compatible In-network addressing scheme 16- bit 128- bit 16- bit 16-bit 16-bit 16-bit 16-bit Available source code ü ü û Open issue û û Open issue Free-payment contributions û ü û ü û û ü Memory and CPU usage ü ü ü û û û ü Cost ü ü ü ü û û ü Flexibility ü ü ü ü û û ü Large-scale networks û û û û ü ü ü Energy-saving support û û û ü ü ü ü 9

10 Motivation Wireless Mesh Sensor Networks (WMSNs) The IEEE released in 2009 the IEEE standard to extend traditional Low-Rate Wireless Personal Area Networks (LR-WPANs) to scalable, robust, energy-efficient and interoperable WMSNs Despite the sought after features already offered by this standard, there is still very few experimental work accessing the performance of IEEE networks Lack of an open-source implementation available to the scientific and development communities 10

11 The IEEE LR-WPAN Mesh standard Anatomy of the current communication stack OSI Reference Model APPLICATION LAYER PRESENTATION LAYER LR-WPAN Mesh Application SESSION LAYER TRANSPORT LAYER NETWORK LAYER DATA LINK LAYER PHYSICAL LAYER IEEE Low-Rate Wireless Personal Area Network Mesh layer IEEE Medium Access Control (MAC) layer IEEE Physical (PHY) layer 11

12 The IEEE LR-WPAN Mesh standard Mesh network formation [14] + [Branch B] Branch 0 A ( ) Branch B [11] + [3] = [14] [8] + [3] = [11] 1 (1-15) 4 (4-15) 7 (9-15) [1] 10 (10) 11 (11) [1] [1] + [1] + [3] + [3] = [8] [1] + [3] = [4] 12 (12-15) 15 (15) [1] Mesh Coordinator Mesh device End device 12

13 The IEEE LR-WPAN Mesh standard Asynchronous Energy Saving (ASES) mode Conceived for the majority of traditional WSN applications Wakeup Interval (WI) RECEIVER Wakeup Notification (WN) SENDER ID AD Active Duration (AD) AD WN ID WI WN AD WN AD ID DATA Ack Data arrival Wait for the receiver s WN ID WN AD WI = meshbaseactiveduration 2 WO [ms] AD = meshbaseactiveduration 2 AO [ms] 0 Active Order (AO) Wakeup Order (WO) 14 time time Transmission by means of the unslotted CSMA-CA 13

14 IEEE Architecture for TinyOS IEEE implementation (TKN154) by J.-H. Hauer 14

15 Performance Evaluation The hidden terminal problem The HT problem gives rise to message collisions, leading to further retransmissions and messages lost High energy waste TX 1 TX 1 WN ID DATA DATA AD DATA ID time RX RX ID WN AD time TX 2 TX 2 AD DATA DATA DATA ID time Hidden terminals 15

16 Performance Evaluation 25 m 25 m 25 m 25 m 25 m Scenario (1.i) Scenario (1.ii) 25 m Receiver Sender Scenario (2) Deployed TelosB devices in an indoor scenario Traffic generation rate: 0.1, 1 and 2 messages per second (127 bytes at the IEEE PHY layer) All nodes configured with WO = 4 (WI = 80 ms) and AO = 3 (AD = 40 ms) 16

17 Results: Single-hop scenario 17

18 Results: Mesh scenario 18

19 Conclusions and Future Work Developed first opensource implementation of the IEEE LR-WPAN Mesh standard for TinyOS Assessed WMSN operation considering HT problems HT problems degrade significantly the WMSN performance q Complete the implementation of the IEEE standard q Investigate and evaluate solutions to alleviate the HT problems in an IEEE networks The complete software can be found in the following repository: 19

20 Thanks! 20