Multirate digital filters for symbol timing synchronization in software defined radios

Harris, Fred; Rice, Michael

doi:10.1109/49.974601

Cited by 87 publications

(47 citation statements)

References 24 publications

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“…Additionally, there are clearly bounds on both the BER for a given number of samples per symbol, as well as the number of samples required to negate a given offset size. 2 1.5695e-03 -3.7582e-04 1.6830e+00 a 3 -9.1463e-03 -1.0193e-01 2.5810e-09 a 4 6.6216e-03 -6.6188e-02 3.6926e+00 a 5 1.8473e-04 3.4661e-01 6.4456e+02 a 6 -2.0971e-01 -2.5740e-01 7.7760e+00 a 7 -5.8369e+00 -2.5051e+01 -a 8 -4.3513e-01 -1.0015e+01 -a 9 2.1307e+00 9.9820e+00 -a 10 1.0110e-01 -1.4948e+00 -…”

Section: Vmentioning

confidence: 99%

Effect of sample timing on LS channel estimation

Uher

Wysocki

2009

2009 3rd International Conference on Signal Processing and Communication Systems

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Abstract-As block coding and intelligent receiver combining in multi-antenna systems moves from the theorectical into the physical domain, it is necessary to apply robust analysis to the problems encountered with the development of real radio systems that are often overlooked during theoretical development of methods and processes. One such problem is the lack of synchronization between the transmitter and receiver sampling clocks. This text attempts to analyze the significance of poorly correcting for differences in the transmit and receive sample clocks by simulating the BER of an Alamouti space-time coded system under a variety of sample rates and clock offsets. The results can be used to estimate the impact on link quality by a given sampler's estimation error using the empirical model given.

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Section: Vmentioning

confidence: 99%

Effect of sample timing on LS channel estimation

Uher

Wysocki

2009

2009 3rd International Conference on Signal Processing and Communication Systems

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“…function is replaced by its small signal approximation tanh(x) ≈ x for low signal-to-noise ratio (SNR) and tanh(x) ≈ sign(x) for high SNR. The authors in [29] proposed full digital timing recovery techniques based on polyphase FB and have shown various timing error detection (TED) methods via FBs. In this paper, we adopt the TED formed by taking the product between the MF output and the derivative MF output, i.e., Figure ten of [29].…”

Section: Pr-nmdfb-based Symbol Timing Recoverymentioning

confidence: 99%

“…The conventional analog solution controls a sampleand-hold circuit located at the output of the analog MF to identify the optimum sampling instant. It is also well known that [29,30] the log-likelihood function for unknown timing phase τ for equally likely S k ∈ {−1, + 1} is where E is the symbol energy, N 0 is the power spectral density of zero-mean Gaussian noise, and y(kT + τ) is the analog MF output. The estimateτ that maximizes Λ(τ) is the timing phase that forces the derivative of Λ(τ) to zero.…”

Section: Pr-nmdfb-based Symbol Timing Recoverymentioning

confidence: 99%

Non-maximally decimated filter bank-based single-carrier receiver: a pathway to next-generation wideband communication

Chen

Harris

Venosa

et al. 2014

EURASIP J. Adv. Signal Process.

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We present the design of a wideband digital modem based on non-maximally decimated filter bank (NMDFB) with perfect reconstruction (PR) property. The PR-NMDFB contains an analysis filter bank (AFB) and a synthesis filter bank (SFB) whose efficient polyphase forms are named as polyphase analysis channelizer (PAC) and polyphase synthesis channelizer (PSC). The waveform being processed is the legacy square root Nyquist-shaped quadrature amplitude modulation (QAM). In contrast to orthogonal frequency division multiplexing (OFDM) systems, the shaped QAM transmission has much superior performance properties in throughput, peak-to-average power ratio (PAPR), and synchronization. We will show the PR-NMDFB is capable of efficiently performing several key tasks of a digital receiver with dramatic workload reduction. This includes digital filtering, carrier recovery, and symbol timing recovery. Moreover, the nature of NMDFB allows the signal processing to operate a significantly reduced sample rate, which is a desired characteristic for replacing current FIR implementation in wideband systems.

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Section: Introductionmentioning

confidence: 99%

“…We also use the upsampled version of the matched filter as an interpolator [2], enabling the implementation of a feedforward timing acquisition method, that is faster than the feedback approach discussed and an all-digital implementation of carrier synchronization for digital radio systems is proposed in [18]. A comparison of different carrier recovery techniques is presented in [19].…”

Section: Introductionmentioning

confidence: 99%

Iterative detection of turbo-coded offset QPSK in the presence of frequency and clock offsets and AWGN

Vasudevan

2010

SIViP

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The key contribution of this work is to develop transmitter and receiver algorithms in discrete-time for turbocoded offset QPSK signals. The proposed synchronization and detection techniques perform effectively at an SNR per bit close to 1.5 dB, in the presence of a frequency offset as large as 30 % of the symbol-rate and a clock offset of 25 ppm (parts per million). Due to the use of up-sampling and matched filtering and a feedforward approach, the acquisition time for clock recovery is just equal to the length of the preamble. The carrier recovery algorithm does not exhibit any phase ambiguity, alleviating the need for differentially encoding the data at the transmitter. The proposed techniques are well suited for discrete-time implementation. Index TermsOffset QPSK (quadrature phase shift keying), frequency offset, clock offset, synchronization, matched filtering, additive white Gaussian noise (AWGN). I. INTRODUCTIONGeosynchronous satellites provide line-of-sight communications with the ground stations. Such communication links offer distortionless transmission, with the only impairment being AWGN. Whereas transmit power is not so much of an issue at the ground station, it is a precious commodity on-board the satellite. With the growing demand for satellite broadcast services, it has become necessary for the end users to receive signals directly from the satellite. This calls for a vastly reduced size and cost of the receiving equipment at the ground station (which is usually the users premises or the handset) and superior modulation, coding and synchronization techniques. With the discovery of turbo codes, the aforementioned scenario has become a reality.In order to further improve the performance and bring down the cost of the receivers, we propose offset QPSK as the modulation technique, which allows the use of power efficient non-linear amplifiers and dataaided synchronization algorithms which have a faster acquisition time than the non-data-aided counterparts proposed in [1]. We also use the upsampled version of the matched filter as an interpolator [2], enabling the implementation of a feedforward timing acquisition method, that is faster than the feedback approach discussed and an all-digital implementation of carrier synchronization for digital radio systems is proposed in [18]. A comparison of different carrier recovery techniques is presented in [19]. A carrier recovery algorithm for M -ary QAM with a capability to track large frequency offsets is discussed in [20]. A non-data-aided carrier recovery method for modified 128-QAM is proposed in [21].Timing recovery can be broadly classified into synchronous and asynchronous methods. In the synchronous methods, the local clock at the receiver is regenerated from the incoming signal. Such techniques are implemented in hardware and are usually employed in analog modems [22]. In the asynchronous approach, the local clock at the receiver is free running, due to which the ratio of the receiver sampling frequency to the incoming symbol-rate is not an ...

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Multirate digital filters for symbol timing synchronization in software defined radios

Cited by 87 publications

References 24 publications

Effect of sample timing on LS channel estimation

Effect of sample timing on LS channel estimation

Non-maximally decimated filter bank-based single-carrier receiver: a pathway to next-generation wideband communication

Iterative detection of turbo-coded offset QPSK in the presence of frequency and clock offsets and AWGN

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