OFDM PAPR Reduction by Shifting Null Subcarriers Among Data Subcarriers

Wang, Bo; Ho, Pin–Han; Lin, Chih-Hao

doi:10.1109/lcomm.2012.060812.120874

Cited by 22 publications

(10 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5c, respectively. From the existing PAPR literature on OFDM systems, it is known that swapping the location of data carrying and reserved null SCs can lead to significant PAPR reduction [37], [38]. It is the same observation we make here, except that the null SCs are determined by the SCMA codebook and the associated SC placement strategy.…”

Section: Simulation Resultssupporting

confidence: 54%

“…SCMA constellations are designed with a number of criteria [3] that will be affected by the constellation shaping and is beyond the scope of the discussion here. Similarly, techniques that involve using null SCs such as tone reservation [39] or the dynamic swapping of data and null SCs [37], [38] is difficult to extend to the SCMA-OFDM paradigm. This is because the null SCs are an integral part of every SCMA block and cannot be rearranged randomly for PAPR reduction purposes.…”

Section: Exploiting Statistical Dependency In Papr Reduction Schementioning

confidence: 99%

See 1 more Smart Citation

Resource Allocation-Based PAPR Analysis in Uplink SCMA-OFDM Systems

et al. 2019

View full text Add to dashboard Cite

Sparse code multiple access (SCMA) is a non-orthogonal multiple access (NOMA) uplink solution that overloads resource elements (RE's) with more than one user. Given the success of orthogonal frequency division multiplexing (OFDM) systems, SCMA will likely be deployed as a multiple access scheme over OFDM, called an SCMA-OFDM system. One of the major challenges with OFDM systems is the high peak-to-average power ratio (PAPR) problem, which is typically studied through the PAPR statistics for a system with a large number of independently modulated sub-carriers (SCs). In the context of SCMA systems, the PAPR problem has been studied before through the SCMA codebook design for certain narrowband scenarios, applicable more for low-rate users. However, we show that for high-rate users in wideband systems, it is more meaningful to study the PAPR statistics. In this paper, we highlight some novel aspects to the PAPR statistics for SCMA-OFDM systems that is different from the vast body of existing PAPR literature in the context of traditional OFDM systems. The main difference lies in the fact that the SCs are not independently modulated in SCMA-OFDM systems. Instead, the SCMA codebook uses multi-dimensional constellations, leading to a statistical dependency between the data carrying SCs. Further, the SCMA codebook dictates that an UL user can only transmit on a subset of the available SCs. We highlight the joint effect of the two major factors that influence the PAPR statistics-the phase bias in the multi-dimensional constellation design along with the resource allocation strategy. The choice of modulation scheme and SC allocation strategy are static configuration options, thus allowing for PAPR reduction opportunities in SCMA-OFDM systems through the setting of static configuration parameters. Compared to the class of PAPR reduction techniques in the OFDM literature that rely on multiple signalling and probabilistic techniques, these gains come with no computational overhead. In this paper, we also examine these PAPR reduction techniques and their applicability to SCMA-OFDM systems. INDEX TERMS Sparse code multiple access (SCMA), peak-to-average power ratio (PAPR), orthogonal frequency division multiplexing (OFDM), sub-carrier (SC), uplink (UL), selective mapping (SLM), interleaving (IL).

show abstract

Section: Simulation Resultssupporting

confidence: 54%

Section: Exploiting Statistical Dependency In Papr Reduction Schementioning

confidence: 99%

Resource Allocation-Based PAPR Analysis in Uplink SCMA-OFDM Systems

et al. 2019

View full text Add to dashboard Cite

show abstract

“…This makes PSUN a type of ISC, as listed in Table 3. Various manners of inserting null tones for different purposes have been studied in the literature [27][28][29]. In this work, PSUN allocates the null tones in such a way that the radar interference is minimized.…”

Section: Precoded Subcarrier Nulling (Psun)mentioning

confidence: 99%

PSUN: An OFDM-Pulsed Radar Coexistence Technique with Application to 3.5 GHz LTE

Kim

Choi

Dietrich

2016

Mobile Information Systems

View full text Add to dashboard Cite

This paper proposes Precoded SUbcarrier Nulling (PSUN), an orthogonal frequency-division multiplexing (OFDM) transmission strategy for a wireless communications system that needs to coexist with federal military radars generating pulsed signals in the 3.5 GHz band. This paper considers existence of Environmental Sensing Capability (ESC), a sensing functionality of the 3.5 GHz band coexistence architecture, which is one of the latest suggestions among stakeholders discussing the 3.5 GHz band. Hence, this paper considers impacts of imperfect sensing for a precise analysis. Imperfect sensing occurs due to either a sensing error by an ESC or a parameter change by a radar. This paper provides a framework that analyzes performance of an OFDM system applying PSUN with imperfect sensing. Our results show that PSUN is still effective in suppressing ICI caused by radar interference even with imperfect pulse prediction. As an example application, PSUN enables LTE downlink to support various use cases of 5G in the 3.5 GHz band.

show abstract

“…Therefore, as listed in Table III, PSUN is still a form of ISC. An OFDM system usually inserts null tones in various manners for different purposes [20]- [22]. In this work it is obvious that radar interference is dominant, thus the PSUN allocates the null tones in such a way that the radar interference is minimized.…”

Section: A Rationale Behind Psunmentioning

confidence: 99%

PSUN: An OFDM scheme for coexistence with pulsed radar

Kim

Park

Bian

2015

2015 International Conference on Computing, Networking and Communications (ICNC)

View full text Add to dashboard Cite

We propose Precoded SUbcarrier Nulling (PSUN), a transmission strategy for OFDM-based wireless communication networks (SCN, Secondary Communication Networks) that need to coexist with pulsed radar systems. It is a novel null-tone allocation method that effectively mitigates inter-carrier interference (ICI) remaining after pulse blanking (PB). When the power from the radar's pulse interference is high, the SCN Rx needs to employ PB to mitigate the interference power. Although PB is known to be an effective technique for suppressing pulsed interference, it magnifies the effect of ICI in OFDM waveforms, and thus degrades bit error rate (BER) performance. For more reliable performance evaluation, we take into account two characteristics of the incumbent radar significantly affect the performance of SCN: (i) antenna sidelobe and (ii) out-of-band emission. Our results show that PSUN effectively mitigates the impact of ICI remaining after PB.

show abstract

OFDM PAPR Reduction by Shifting Null Subcarriers Among Data Subcarriers

Cited by 22 publications

References 5 publications

Resource Allocation-Based PAPR Analysis in Uplink SCMA-OFDM Systems

Resource Allocation-Based PAPR Analysis in Uplink SCMA-OFDM Systems

PSUN: An OFDM-Pulsed Radar Coexistence Technique with Application to 3.5 GHz LTE

PSUN: An OFDM scheme for coexistence with pulsed radar

Contact Info

Product

Resources

About