| 1. |
- Huan, Yuxiang, et al.
(författare)
-
A 101.4 GOPS/W Reconfigurable and Scalable Control-Centric Embedded Processor for Domain-Specific Applications
- 2016
-
Ingår i: IEEE Transactions on Circuits and Systems Part 1. - : IEEE. - 1549-8328 .- 1558-0806. ; 63:12, s. 2245-2256
-
Tidskriftsartikel (refereegranskat)abstract
- Adapting the processor to the target application is essential in the Internet-of-Things (IoT), and thus requires customizability in order to improve energy efficiency and scalability to provide sufficient performance. In this paper, a reconfigurable and scalable control-centric architecture is proposed, and a processor consisting of two cores and an on-chip multi-mode router is implemented. Reconfigurability is enabled by a programmable sequence mapping table (SMT) which reorganizes functional units in each cycle, thus increasing hardware utilization and reducing excessive data movement for high energy efficiency. The router facilitates both wormhole and circuit switching to construct intra- or inter-chip interconnections, providing scalable performance. Fabricated in a 65-nm process, the chip exhibits 101.4 GOPS/W energy efficiency with a die size of 3.5 mm(2). The processor carries out general-purpose processing with a code size 29% smaller than the ARM Cortex M4, and improves the performance of application-specific processing by over ten times when implementing AES and RSA using SMTs instead of general-purpose C. By utilizing the on-chip router, the processor can be interconnected up to 256 nodes, with a single link bandwidth of 1.4 Gbps.
|
|
| 2. |
- She, Huimin, et al.
(författare)
-
Analytical Evaluation of Retransmission Schemes in Wireless Sensor Networks
- 2009
-
Ingår i: 2009 IEEE VEHICULAR TECHNOLOGY CONFERENCE. - 9781424425167 ; , s. 38-42
-
Konferensbidrag (refereegranskat)abstract
- Retransmission has been adopted as one of the most popular schemes for improving transmission reliability in wireless sensor networks. Many previous works have been done on reliable transmission issues in experimental ways, however, there still lack of analytical techniques to evaluate these solutions. Based on the traffic model, service model and energy model, we propose an analytical method to analyze the delay and energy metrics of two categories of retransmission schemes: hop-by-hop retransmission (HBH) and end-to-end retransmission (ETE). With the experiment results, the maximum packet transfer delay and energy efficiency of these two scheme are compared in several scenarios. Moreover, the analytical results of transfer delay are validated through simulations. Our experiments demonstrate that HBH has less energy consumption at the cost of lager transfer delay compared with ETE. With the same target success probability, ETE is superior on the delay metric for low bit-error-rate (BER) cases, while HBH is superior for high BER cases.
|
|
| 3. |
- She, Huimin, et al.
(författare)
-
Modeling and Analysis of Rayleigh Fading Channels using Stochastic Network Calculus
- 2011
-
Konferensbidrag (refereegranskat)abstract
- Deterministic network calculus (DNC) is not suitable for deriving performance guarantees for wireless networks due to their inherently random behaviors. In this paper, we develop a method for Quality of Service (QoS) analysis of wireless channels subject to Rayleigh fading based on stochastic network calculus. We provide closed-form stochastic service curve for the Rayleigh fading channel. With this service curve, we derive stochastic delay and backlog bounds. Simulation results verify that the bounds are reasonably tight. Moreover, through numerical experiments, we show the method is not only capable of deriving stochastic performance bounds, but also can provide guidelines for designing transmission strategies in wireless networks.
|
|
| 4. |
- She, Huimin, et al.
(författare)
-
Performance Analysis of Flow-Based Traffic Splitting Strategy on Cluster-Mesh Sensor Networks
- 2012
-
Ingår i: International Journal of Distributed Sensor Networks. - : Hindawi Publishing Corporation. - 1550-1329 .- 1550-1477. ; , s. 232937-
-
Tidskriftsartikel (refereegranskat)abstract
- Performance analysis is crucial for designing predictable and cost-efficient sensor networks. Based on the network calculus theory, we propose a flow-based traffic splitting strategy and its analytical method for worst-case performance analysis on cluster-mesh sensor networks. The traffic splitting strategy can be used to alleviate the problem of uneven network traffic load. The analytical method is able to derive close-form formulas for the worst-case performance in terms of the end-to-end least upper delay bounds for individual flows, the least upper backlog bounds, and power consumptions for individual nodes. Numerical results and simulations are conducted to show benefits of the splitting strategy as well as validate the analytical method. The numerical results show that the splitting strategy enables much better balance on network traffic load and power consumption. Moreover, the simulation results verify that the theoretic bounds are fairly tight.
|
|
| 5. |
- She, Huimin, et al.
(författare)
-
Traffic splitting with network calculus for mesh sensor networks
- 2007
-
Ingår i: Proceedings of Future Generation Communication and Networking, FGCN 2007. - : IEEE Computer Society. - 9780769530482 ; , s. 371-376
-
Konferensbidrag (refereegranskat)abstract
- In many applications of sensor networks, it is essential to ensure that messages are transmitted to their destinations as early as possible and the buffer size of each sensor node is as small as possible. In this paper, we firstly propose a mesh sensor network system model. Based on this system model, the expressions for deriving the delay bound and buffer requirement bound are presented using network calculus. In order to balance traffic load and improve resource utilization, three traffic splitting mechanisms are proposed The numerical results show that the delay bound and buffer requirement bound are lowered while applying those traffic splitting mechanisms. And thus the performance of the whole sensor network is improved.
|
|
| 6. |
|
|
| 7. |
- Zhang, Zhi, et al.
(författare)
-
A low delay multiple reader passive RFID system using orthogonal TH-PPM IR-UWB
- 2010
-
Ingår i: Proceedings - International Conference on Computer Communications and Networks, ICCCN. - Zurich.
-
Konferensbidrag (refereegranskat)abstract
- Current passive RFID systems face the challenges to locate mobile objects in real time in indoor environments, including the realization of low delay as well as effective cooperation among readers and accurate ranging ability in the physical layer. In order to overcome these challenges, this paper presents a low delay multi-reader passive RFID system using ultra high frequency (UHF) radio as the forward link from readers to tags and orthogonal time hopping pulse-position modulation (TH-PPM) impulse ultra-wideband radio (IR-UWB) over the dynamic framed slotted ALOHA algorithm as the backward link from tags to readers. The asymmetric radio links overlap parts of the forward and backward transmission and avoid reader-tag collisions. Readers cooperate via network synchronization by a server and a contention-based update strategy to acknowledge tags. An optimal system configured with 4 readers using 16 orthogonal TH sequences is suggested and operates 3 times faster than the theoretical potential of EPC Class-1 Generation-2 protocol with the listen-before-talk scheme.
|
|
| 8. |
- Zhang, Zhi, et al.
(författare)
-
Code division multiple access/pulse position modulation ultra-wideband radio frequency identification for Internet of Things : concept and analysis
- 2012
-
Ingår i: International Journal of Communication Systems. - : Wiley. - 1074-5351 .- 1099-1131. ; 25:9, s. 1103-1121
-
Tidskriftsartikel (refereegranskat)abstract
- Radio frequency identification (RFID) is a compelling technology for Internet of Things (IoT). Ultra-wideband (UWB) technology is one promising wireless technique for future RFID, especially for high-throughput sensing applications. On-off keying UWB RFID system provides high pulse rate but suffers severe collisions that limit the system throughput. This paper proposes to utilize low pulse rate code division multiple access/pulse position modulation UWB in the tag-to-reader link to provide multiple tag access capability and build a high-throughput RFID system for IoT. We analyze asynchronous matched filter receiver and decorrelating receiver for multi-tag detection and design an effective medium access control scheme to optimize the network throughput. We propose an effective dynamic frame size adjustment algorithm on the basis of theoretical analysis and determine the preferable length of Gold codes. With a similar data rate, the throughput of the proposed system using the decorrelating receiver is 8.6 times higher than that of the electronic product code class 1 generation 2 system. Only using 1/10 pulse rate and 1/15 data rate, the proposed system outperforms the on-off keying UWB RFID system 1.4 times in terms of throughput.
|
|
| 9. |
- Zhang, Zhi, et al.
(författare)
-
COSMO : CO-simulation with MATLAB and OMNeT++ for indoor wireless networks
- 2010
-
Ingår i: 2010 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE GLOBECOM 2010. - 9781424456383
-
Konferensbidrag (refereegranskat)abstract
- Simulations are widely used to design and evaluate new protocols and applications of indoor wireless networks. However, the available network simulation tools face the challenges of providing accurate indoor channel models, three-dimensional (3-D) models, model portability, and effective validation. In order to overcome these challenges, this paper presents a new CO-Simulation framework based on MATLAB and OMNeT++ (COSMO) to rapidly build credible simulations for indoor wireless networks. A hierarchical ad hoc passive RFID network for indoor tag locating is described as a case study, demonstrating the significance and efficiency of COSMO compared with other network simulators. COSMO surpasses other network simulators in terms of workload and validity.
|
|
| 10. |
- Zhang, Zhi, et al.
(författare)
-
Item-Level Indoor Localization With Passive UHF RFID Based on Tag Interaction Analysis
- 2013
-
Ingår i: IEEE Transactions on Industrial Electronics. - 0278-0046 .- 1557-9948. ; 61:4, s. 2122-2135
-
Tidskriftsartikel (refereegranskat)abstract
- Radio-frequency identification (RFID) with a received signal strength indicator (RSSI) is a low-cost and low-complexity approach for item-level indoor localization. Although RSSI-based algorithms suffer from multipath effect and other environmental factors, reference tags and RSSI changes can be utilized to further improve the localization accuracy. However, the current algorithms lack deep analysis of the influence of tag interaction on localization accuracy and faces the challenge of simultaneously locating multiple close targets. In this paper, we propose an analysis method about how tag interaction affects a tag antenna radiation pattern and an RSSI change. The tag interaction analysis guides us to improve the design of RSSI-based localization algorithms. We take the k-nearest neighbor (k-NN) algorithm and the Simplex algorithm as two examples. The experimental results show that the revised k-NN and the revised Simplex algorithms are robust to different numbers, spacing, and materials of target objects, and they are superior to other RFID localization schemes, considering cost, capability of simultaneous localization of multiple targets, and location estimation errors.
|
|
