A method for synchronizing low cost energy aware sensors used in industrial process monitoring

Nordman, Mikael; Kozłowski, Wojciech; Vahamaki, O.

doi:10.1109/iecon.2001.976462

Cited by 8 publications

(2 citation statements)

References 5 publications

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“…This asynchronism in time and data rate among several sensors imposes an interesting communication design problem. There exist some works on synchronization in wireless sensor networks but they utilize two way links to perform synchronization (e.g., [1 ] After obtaining dk,sync, the coarse timing offset estimate of the kth sensor is given by…”

Section: Introductionmentioning

confidence: 99%

Time hopping direct-sequence CDMA for asynchronous transmitter-only sensors

Zeng¹,

Minn²,

Tamil³

2008

MILCOM 2008 - 2008 IEEE Military Communications Conference

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II. SYSTEM DESCRIPTION AND SIGNAL MODELwhere p (t) is the rectangular pulse shape, and Tb is the bit duration. bk,n is the DPSK modulated data defined asWe consider an uplink asynchronous system with K sensors and a sink node or fusion center. Each sensor has transmissiononly capability. The data signal of each sensor is defined assensors are typically used in location systems (e.g., [2]), however the signals from sensors are typically assumed to be received without any multi-user interference, and their main focus is how to efficiently fuse these signals in extracting the unknown parameters. The asynchronism issue was also addressed by means of medium access control (e.g., [3]), but this approach requires two way links. The synchronization of asynchronous DS-UWB systems was addressed in [4] by using two types of training signals. However, the users have both transmitter and receiver, and they receive common synchronization signal to estimate the timing. So their asynchronism are limited to small range. Different from the existing works, we will develop a communication scheme for asynchronous transmitter-only sensors. The sensors can transmit completely asynchronously. The communication schemes we present in this paper are based on DS-CDMA or a combination of DS-CDMA and specifically designed time hopping codes. We also propose a new detector that has better BER performance than conventional matched filter (MF) detector by utilizing channel energy capturing and multipath diversity. We compare the energy consumption, computation complexity, and BER performance of the proposed time hopping DS-CDMA scheme with the conventional DS-CDMA scheme.The rest of this paper is organized as follows. The system and signal models are described in Section II. The proposed time hopping transmission scheme is present in Section III. The energy consumption and complexity comparisons are discussed in Section IV and Section V, respectively. Simulation results and discussion are given in Section VI, and conclusions are drawn in Section VII.Abstract-This paper investigates transmission schemes for asynchronous transmitter-only wireless sensor nodes. We propose a time hopping DS-CDMA scheme by utilizing time hopping code design. Each sensor transmits only in pre-assigned active time slots and switches to sleep mode in idle time slots. By utilizing the proposed scheme, each sensor can always have several collision-free time slots. We also propose a new detector that has better HER performance than conventional matched filter (MF) detector by utilizing channel energy capturing and multipath diversity. We compare BER performance, power consumptions, and computational complexities of the proposed transmission scheme with conventional DS-CDMA scheme. The proposed scheme achieves significant energy and complexity savings while keeping similar HER performance with conventional DS-CDMA scheme.

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Section: Introductionmentioning

confidence: 99%

Time hopping direct-sequence CDMA for asynchronous transmitter-only sensors

Zeng¹,

Minn²,

Tamil³

2008

MILCOM 2008 - 2008 IEEE Military Communications Conference

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“…INTRODUCTION Advances in both software and hardware technology have made a reality the Distributed Measurement System (DMS) in which the Measurement Instruments (MIs), besides to be remotely controlled by different clients, can co-operate among them to execute the measurement procedures [1]- [8]. The synchronization of the co-operating MIls is a new challenging requirement that emerges in the contest of industrial automation application [9]- [11], monitoring system [12]- [15], inspection and management of strategic power plant [16]- [2 1]. …”

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confidence: 99%

Delay of the Software Commands in the Path PC-Measurement Instruments

Grimaldi

Lamonaca

2008

2008 IEEE Instrumentation and Measurement Technology Conference

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On the basis ofthe standardIEEE 1588, the PC co-operating in the Distributed Measurement System can work on synchronized modality. Nevertheless, the hardware and the software architecture of the path involved in the communication PC-Measurement Instrument (MI) can delay the commands. The research aims to investigate about the time delay occurring in the communication between the PC and the MI In particular, the criteria to modify and to set up the software to reduce both the mean value and the standard deviation ofthe time delay occurring in the processing steps performed into the PC is taken into account. Experimental tests are performed with different setting up of the Linux Operating System and using different MIs The experimental results highlight that delay characterized by sub-microsecond mean value andnanosecond standard deviation can be achieved

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