A PSK group modem based on digital signal processing: Algorithm, hardware design, implementation and performance

Takahata, Fumio; Yasunaga, M.; Hirata, Y.; Ohsawa, Tomoki; Namiki, J.

doi:10.1002/sat.4600060304

Cited by 13 publications

(3 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Other studies and implementations in the digital field have been provided in the U.K.7 and Japan. 8 The objective of the studies (presented in Table X) was basically an MCD at low data rate, with a small number of channels, so that an implementation with DSP processors was suitable. Concerning the demultiplexer architecture it is worth noticing that, in the first example, the multistage structure was implemented, whereas in the second one, the polyphase network + FFT has been proposed.…”

Section: Systemmentioning

confidence: 99%

Saw and digital technologies in mutlicarrier demodulators

Saggese¹,

Chiassarini²

1989

Int. J. Satell. Commun.

View full text Add to dashboard Cite

One key technology, for the implementation of future on-board processing payloads, is the multicarrier demodulator (MCD). The MCD is instrumental in allowing FDMAEDM access schemes which optimize the use of on-board and ground resources in VSAT networks. This paper deals with the analogue and digital implementations of MCD, trying to assess the fields of application of each of the two technologies. KEY WORDS Multicarrier demodulator SAW devices Digital on-board processing *Now with Space Engineering 91, Via Dei Berio, 00155 Rome, Italy link. Further baseband switching is made possible, opening the avenue to the implementation of complex on-board processing functions.An example of the utility of the MCD is given by the 'mobile satellite communications' service, where there are, on one side, mobile users and, on the other, a few earth-stations (gateways to existing terrestrial network).

show abstract

Section: Systemmentioning

confidence: 99%

Saw and digital technologies in mutlicarrier demodulators

Saggese¹,

Chiassarini²

1989

Int. J. Satell. Commun.

View full text Add to dashboard Cite

show abstract

“…Conventional group demodulators can be divided into two categories. One is based on group frequency conversion using the fast Fourier transform (FFT) algorithm [3] [4], and the other utilizes frequency division multiplexing -time division multiplexing (FDM-TDM) conversion using the chirp Fourier transform [ 1] [2]. Group demodulators based on the chirp Fourier transform (CFT group demodulator) have advantages in terms of low power consumption and high operation speed which allows a large number of channels to be handled.…”

Section: Introductionmentioning

confidence: 99%

A new group demodulator with multi-symbol chirp Fourier transform for mobile communication systems

Kumagai

Kobayashi

Proceedings of ICUPC '95 - 4th IEEE International Conference on Universal Personal Communications

View full text Add to dashboard Cite

This paper proposes a group demodulator having a dual-parallel structure that employs the multi-symbol chirp Fourier transform and also evaluates the power consumption. Proposed group demodulator is suitable for hardware implementation and can demodulate band-limited and bit asynchronous signals with reasonably small degradation. Computer simulation results show that the bit error rate (BER) degradation of the proposed group demodulator employing 6-symbol chirp Fourier transformation is less than 0.5 dB at BER=10m3 even when root Nyquist (a=0.6) filtered bit asynchronous FDMA signals are received. The power consumption is lower than that of conventional demodulators when many carriers are handled.

show abstract

“…Conventional group demodulators can be divided into two categories. One is based on group frequency converting using the fast Fourier transform (FFT) algorithm [3] [4], and the other utilizes the frequency division multiples -time division multiples (FDM-TDM) conversion using chirp Fourier transform [ 1] [2]. The group demodulator based on chirp Fourier transform (CFT group demodulator) has advantages in hardware size and maximum operarion speed to handle a number of channels.…”

mentioning

confidence: 99%

A new group demodulator employing multi-symbol chirp Fourier transform

Kobayashi

Kumagai

Kato

1994 IEEE GLOBECOM. Communications: The Global Bridge

View full text Add to dashboard Cite

T1ii.r p a p e r l m p m s U g i m p denrodrrlntor that ernploys multisymbol chirp Fourier iruiisji)rni io deinodulate pulse shuppd unci bit nsj~nchronous sigriols: this is not possible witli coriveiitioriul ~~O L I~J denioduluiois based on chirp Foitrirr tmi.$orni. Moreover, n iiovel clock iiniirig rstiriintioii sc.lrenie for the p o j~o s e d groirp deniodirlator is p1.oposed. The clock tirniiig is estinratedfi.onr the phase of two frequency coriijwirirts of tlre p~raniblr sigrial wid1 a siniple calculation. Computer siniirlatioii r~esults show that the iotul bit rrror rate degradutiori of the pvoposetl group deniodiilator einploying 7-symbol chirp Fourier trunsform is less tlian 0.3dB ot BER=IO.J even rvlieii roof Nyquist (@=OS) ,filtrr.ed nsynchroi~oi4s FDMA signals are received. Introd~ictioiiIn digital mobile and personal communication systems, the base stations tnust handle many frequency division multiple access (FDMA) signals simultaneously. To demodulate such signals, the group deinodulator [ 1][2][3][4][5] is one powerful solution to minimize the hardware size of the base stations. Conventional group demodulators can be divided into two categories. One is based on group frequency converting using the fast Fourier transform (FFT) algorithm [3][4], and the other utilizes the frequency division multiples -time division multiples (FDM-TDM) conversion using chirp Fourier transform [ 1][2]. The group demodulator based on chirp Fourier transform (CFT group demodulator) has advantages in hardware size and maximum operarion speed to handle a number of channels.Conventional CFT group demodulators, however, have two major problems. First, the modulation signals must be square pulse signals instead of pulse shaped and band-limited signals and carriers must be spaced by multiples of the Nyquist frequency. This Nyquist-spaced square pulse transmission cannot be used for commercial systems because its out of band radiation is significant and frequency allocation flexibility is quite poor. If a conventional CFT group demodulator processes band-limited signals, considerable bit error rate degradation arises from the adjacent channel interference (ACI), the inter symbol interference (13) and decreased eye aperture, as will be described in the following section. Second, the symbol timing phase of each FDMA signal must be synchronized with the sweep tiinhg phase of the chirp signal at the receiver input. Therefore an accurate timing control loop is required. Due to these problems, conventional CFT group demodulators have not been employed in existing mobile or personal communication systems.To solve these problems, this paper proposes a group demodulator based on mnlti-symbol chirp Fourier transform. By using more than one symbol for chirp Fourier transform and some additional signal processing operations, the proposed group demodulator can demodulate pulse shaped and time asynchronous signals with negligibly small degradation. 2.'Conventional CFT group demodulatorA block diagram of a conventional CFT group dernodulator ...

show abstract

A PSK group modem based on digital signal processing: Algorithm, hardware design, implementation and performance

Cited by 13 publications

References 4 publications

Saw and digital technologies in mutlicarrier demodulators

Saw and digital technologies in mutlicarrier demodulators

A new group demodulator with multi-symbol chirp Fourier transform for mobile communication systems

A new group demodulator employing multi-symbol chirp Fourier transform

Contact Info

Product

Resources

About