Parallelized convolutional interleaver implementation for efficient DDR memory access

Downey, Joe; Shalkhauser, Mary Jo; Bizon, Thomas P.

doi:10.1117/12.2608235

Cited by 2 publications

(2 citation statements)

References 3 publications

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“…This appendix includes a series of derivations for the modulus and quotient calculations of 𝑓(𝑗). The recursive relation for the remainder of 𝑓(𝑗) with a step size 𝑛 for 𝑚 = log (𝑀) is given as 𝑟 (𝑗 + 𝑛) = 𝑓(𝑗 + 𝑛) mod 𝑚 = 𝑓(𝑗) + 𝑔(𝑗) mod 𝑁 mod 𝑚 = [𝑓(𝑗) + 𝑔(𝑗, 𝑛)]mod 𝑚 = 𝑓(𝑗) mod 𝑚 + 𝑔(𝑗, 𝑛) mod 𝑚 = [𝑟 (𝑗) + 𝑟 (𝑗, 𝑛)] mod 𝑚 (10) where 𝑟 , (𝑗) = 𝑔 (𝑗) mod m and 𝑟 (𝑗) = 𝑓(𝑗) mod 𝑚.…”

Section: Discussionmentioning

confidence: 99%

Field-programmable gate array implementation of a single photon-counting receive modem

Simon,

Downey,

Lantz

et al. 2024

Free-Space Laser Communications XXXVI

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We present a field-programmable gate array (FPGA) implementation of a single photon-counting receive modem for a pulse position modulated signal. The modem is compliant with the Consultative Committee for Space Data Systems (CCSDS) High Photon Efficiency (HPE) Optical Communications Coding and Synchronization standard and is capable of a maximum data rate of 267 Mbps. The system is designed on a commercial off-the-shelf FPGA platform and utilizes superconducting nanowire single photon counting detectors, analog to digital converters (ADCs) to sample the detectors, and two FPGAs. Symbol timing recovery, photon counting, convolutional deinterleaving, and codeword synchronization are performed in the first FPGA. The second FPGA performs iterative decoding on each codeword of the serially concatenated pulse position modulated (SCPPM) signal. A digital filter is included to compensate for timing jitter of the detector, and the decoder throughput can be adjusted through reconfigurable parallelization. The decoder also implements a resource-efficient, algorithmic polynomial interleaver and deinterleaver. Both FPGAs can be reconfigured to switch between pulse position modulation (PPM)-16 and PPM-32 with code rates 1/3, 1/2, and 2/3. In this paper, we describe the receiver architecture and FPGA implementation of the timing recovery loop and SCPPM decoder, FPGA utilization for the different modes, and receive modem characterization test results.

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Section: Discussionmentioning

confidence: 99%

Field-programmable gate array implementation of a single photon-counting receive modem

Simon,

Downey,

Lantz

et al. 2024

Free-Space Laser Communications XXXVI

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“…Kb is calculated from the average photon counts in the guard band and Ks is calculated from the difference of the average photon counts in the signal slots and guard band. Convolutional deinterleaving is implemented utilizing an external DDR4 memory operating at 2400 MHz 11 . The deinterleaved symbols with 3 bits per slot and the received channel statistics are sent over the backplane on a high-speed serial link to the decoder FPGA.…”

Section: Fpga-based Receivermentioning

confidence: 99%

A real-time optical ground receiver for photon starved environments

Downey

Tedder

Vyhnalek

et al. 2023

Free-Space Laser Communications XXXV

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The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) has developed a photoncounting optical ground receiver for pulse-position modulated signals. The real-time receiver system includes a fiber interconnect, superconducting nanowire single-photon detectors (SNSPDs), and a real-time field programmable gate array (FPGA) based receiver. The fiber interconnect and SNSPDs are implemented with two different configurations. In the first, a 7-channel few-mode fiber photonic lantern couples the light from the telescope to 7 single-pixel few-mode fiber coupled SNSPDs. In the second configuration, a few-mode fiber couples light to a 16-pixel monolithic SNSPD array. The real-time FPGA-based receiver performs combining of up to 16 SNSPD channels, symbol timing recovery, demodulation, and decoding. The system is scalable with data rates ranging from 20 Mbps to 267 Mbps. It is compliant with the Consultative Committee for Space Data Systems (CCSDS) Optical Communications Coding and Synchronization Standard. This standard will be used in NASA deep space and other low photon flux missions, such as in the Orion Artemis-2 Optical Communications System (O2O) demonstration, planned for the first crewed flight of Orion. This paper describes the scalable real-time optical receiver system and presents characterization test results.

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Parallelized convolutional interleaver implementation for efficient DDR memory access

Cited by 2 publications

References 3 publications

Field-programmable gate array implementation of a single photon-counting receive modem

Field-programmable gate array implementation of a single photon-counting receive modem

A real-time optical ground receiver for photon starved environments

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