1 Introduction
2 OFDM signal characteristic
3 DRM-specific selection criteria of PAPR algorithms
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–It is not allowed to violate the DRM standard such as making modifications to receiver structure, data rate, cell-interleaving and pilot cells.
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–The quality of the audio signal has to be maintained. This means that the MER should not fall below a predetermined level [8].
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– The frequency spectrum mask is required to conform to the DRM standard. The deterioration of spectral properties should remain within a reasonable limit [9].
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– Synchronization performance should not be compromised. In other words, executing the PAPR reduction algorithms should not affect the efficiency of synchronization.
4 Compatibility of PAPR reduction schemes with DRM system
4.1 Signal distortion
4.1.1 Nonlinear companding transform
4.1.2 Peak reduction carrier
4.1.3 Random phase shuffling
4.1.4 Envelop scaling
4.1.5 Clipping and filtering
4.2 Signal scrambling
4.2.1 Hadamard transform
4.2.2 Dummy sequence insertion
4.2.3 SLM and PTS
4.2.4 Interleaving and block coding
4.2.5 Tone reservation
4.2.6 Tone insertion
4.2.7 Active constellation extension
Technique | Method | Standard conformity | Explanation |
---|---|---|---|
Signal distortion | Nonlinear companding transform | No | Need for modification of the receiver |
Peak reduction carrier | No | Need for modification of the transceiver | |
Random phase shuffling | No | Need for modification of the receiver | |
Envelop scaling | No | Applicable only to PSK-modulated signals | |
Clipping and filtering | Yes | No need for modifications | |
Signal scrambling | Hadamard transform | No | Need for modification of the receiver |
Dummy sequence insertion | No | Need for modification of the receiver | |
SLM and PTS | No | Need for modification of the receiver | |
Interleaving and block coding | No | Need for modification of the transceiver | |
Tone reservation | No | Need of Additional subcarriers | |
Tone insertion | No | Need for modification of the receiver | |
ACE | Yes | No need for modifications |
5 Simulation results
5.1 PAPR analysis
Parameter | Prefilter | Postfilter |
---|---|---|
Length [sample] | 0.1 | 0.2 |
Passband edge [kHz] | 8.3 | 4.7 |
Stopband edge [kHz] | 8.7 | 5.2 |
Passband ripple [dB] | 0.001 | 0.001 |
Stopband atten. [dB] | 60 | 15 |
5.2 Spectral property
5.3 Synchronization efficiency
Method | MSE [dB] |
---|---|
Clipping-postfiltering | −83 |
Prefiltering-postclipping | −88 |
ACE postfiltering | −59 |