Constant envelope OFDM signals for radar applications

Mohseni, Reza Moosavi; Sheikhi, A.; Shirazi, Mohammad Ali Masnadi

doi:10.1109/radar.2008.4720802

Cited by 21 publications

(7 citation statements)

References 6 publications

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“…Given the limitations of FPGA processing speeds, the CE IF signal is generated with a polyphase structure to accommodate the DAC's sampling rate. Given a fixed number P, we can obtain exactly P different discretely sampled signals (see (14) and 15…”

Section: Polyphase Structure Of Ce Signals With Compensationmentioning

confidence: 99%

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Digital constant‐envelope modulation scheme for radar using multicarrier OFDM signals

Qian

Jiang

2017

IET signal process.

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Multicarrier signals using orthogonal frequency division multiplexing (OFDM) bring many advantages to radar such as low probability of intercept, improved target detection performance, optimisation of both radar transmitter and receiver etc. A major drawback of multicarrier OFDM signals is their high peak-to-mean envelope power ratio, which reduces the working efficiency of the used power amplifiers. To solve this problem, a digital constant-envelope modulation scheme is proposed for radar using multicarrier OFDM signals. The scheme can transmit multicarrier OFDM signals through power amplifiers being operated near saturation levels (and thus maximising power efficiency) with little spectral distortion, even in the presence of channel mismatch. Given the speed limitations of field programmable gate arrays (FPGAs), the proposed scheme is implemented in an FPGA at intermediate frequency level using a polyphase processing structure.

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Section: Polyphase Structure Of Ce Signals With Compensationmentioning

confidence: 99%

“…In 2008, Mohseni et al . proposed the notion of CE‐OFDM signals, which combine OFDM and phase or frequency modulation [13]. These CE‐OFDM signals have many of the good properties of multicarrier OFDM signals [14], but they are not multicarrier signals in the traditional sense, and no longer have the ability of single subcarrier usage.…”

Section: Introductionmentioning

confidence: 99%

Digital constant‐envelope modulation scheme for radar using multicarrier OFDM signals

Qian

Jiang

2017

IET signal process.

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“…So on the first OFDM symbol, carrier −3 will transmit a −1, and carrier 2 will transmit a 1 j . We observe that pilot_symbols is longer than pilot_carriers and the symbols in pilot_symbols [2] will be mapped according to pilot_carriers [0].…”

Section: System Modelmentioning

confidence: 99%

“…This high PAPR negatively impacting the power efficiency of the radio frequency (RF) power amplifier system that leads to non‐linearities such as spectral broadening, intermodulation distortion and performance degradation. In general, a power backoff is used at the amplifier to reduce the out‐of‐band spectral leakage and the OFDM signal distortion [2]. Such backoff reduces the radiated power as well as the amplifier efficiency.…”

Section: Introductionmentioning

confidence: 99%

Experimental validation of orthogonal frequency division multiplexing with peak‐to‐average power ratio reduction and out‐band distortion control using software defined radio

Reddy

Boppana

2016

IET signal process.

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Orthogonal frequency division multiplexing (OFDM) is an emerging technology in recent wireless communication standards where high data rate is required at low latency and better spectral efficiency. OFDM signals have a generic problem of high peak-to-average power ratio (PAPR) due to the superimposition of the data-modulated subcarriers. This high peak signals may result in amplifier non-linearity which creates many problems such as performance degradation and out-of-band distortion. Hence, the authors addressed this problem by designing and implementing four new PAPR reduction schemes such as phase modulation, rail clipping, sample and hold approach and threshold methods based on amplitude clipping to reduce PAPR and improve the band gap between spectral sidelobes to main lobe significantly. For practical proof of the suggested concepts, they have chosen software-defined radio as an experimental setup in which universal software radio peripheral N210 employed as hardware and GNU radio as software. Experimental results are analysed in terms of significant PAPR reduction and out-of-band spectral leakage control. Besides these, motivation, background and relevant mathematical analysis with rigid justification are presented in this study.

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“…In [9] we have presented another approach to alleviate the undesirable effects due to the high PAPR of OFDM signals. This technique has also been considered for radar systems in [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%