Optimal Power Allocation in Spatial Modulation OFDM for Visible Light Communications

Zhang, Xiao; Dimitrov, Svilen; Sinanović, Sinan; Haas, Harald

doi:10.1109/vetecs.2012.6239965

Cited by 43 publications

(33 citation statements)

References 16 publications

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“…The spatial modulator at the transmitter maps the first log 2 (N t ) most significant bits of each symbol to the spatial constellation point, which is used to select the LED that will be active, while the remaining log 2 (L) bits are mapped to the signal constellation point. The signal constellation point is conveyed by the transmitted digital signal modulation such as pulse amplitude modulation (PAM) [9], PPM [4], and orthogonal frequency division multiplexing (OFDM) [10], among others. For instance, if PAM is used for signal modulation, the signal constellation point determines the intensity level of the optical signal that will be emitted by the active LED.…”

Section: Generation and Detectionmentioning

confidence: 99%

Spatial Modulation – A Low Complexity Modulation Technique for Visible Light Communications

Olanrewaju¹,

Ogunkoya²,

Popoola³

2017

Visible Light Communications

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In visible light communication (VLC), the fundamental limitation on the achievable data rate/spectral efficiency is imposed by the optical source, particularly the phosphorconverted white light emitting diode (LED). These low-cost white LEDs favoured in solid-state lighting have very limited modulation bandwidth of less than 5 MHz, typically. This imposes a severe limitation on the attainable data rate. This is recognised in the literature and has led to the emergence of techniques such as multiple-input-multipleoutput (MIMO) VLC systems as a means of addressing this challenge. The MIMO approach takes advantage of the multi-LED/multi-receiver structure to improve performance. In this chapter, we shall be discussing spatial modulation (SM) as a novel lowcomplexity MIMO technique for the VLC system. The SM technique exploits the spatial location of the individual LED as an additional degree of freedom in data modulation. Moreover, the chapter includes the comparison analysis of the SM technique with other traditional methods of modulation such as on-off keying (OOK) and pulse position modulation (PPM).

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Section: Generation and Detectionmentioning

confidence: 99%

Spatial Modulation – A Low Complexity Modulation Technique for Visible Light Communications

Olanrewaju¹,

Ogunkoya²,

Popoola³

2017

Visible Light Communications

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“…This is done at the expense of limiting the total number of subcarriers used for data transmission by half. However, the ease of combining optical OFDM with higher order modulation schemes like QAM makes it possible for these active subcarriers to be loaded with data according to the VLC channel properties [8], [9]. The resulting real-valued bipolar OFDM signal is biased to transform it to unipolar time-domain signal since LEDs can only convey unipolar signals in light intensity.…”

Section: Description Of Pilot-assisted Papr Reduction Technique Imentioning

confidence: 99%

Pilot symbol utilization for reducing peak-to-average power ratio in optical OFDM

Ogunkoya

Popoola

Shahrabi

et al. 2014

2014 9th International Symposium on Communication Systems, Networks &Amp; Digital Sign (CSNDSP)

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One of the evolved technologies which has the prospect of providing huge data rate is visible light communication (VLC). Use of optical orthogonal frequency-division multiplexing (OFDM) has been demonstrated as one of the viable schemes in achieving high data rate in VLC system. However, the limitation of optical OFDM still remains the high peak-toaverage power ratio (PAPR) which results in signal distortion and increase in error rate. In this paper, we describe a technique that can mitigate high PAPR in optical OFDM using pilot symbol in the indoor VLC environment. The pilot assisted OFDM system gives 2.4 dB PAPR reduction for a 4-QAM. There is indication from the simulation results that not only can the technique reduce high PAPR but it also offers good bit error rate (BER) performance. For the BER performance of 64-QAM, the pilot symbol estimation error leads to about 0.6 dB degradation at BER of 10 −3 .

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“…bits are conveyed by the transmitted signal modulation such as pulse position modulation (PPM) [7], pulse amplitude modulation [2], quadrature amplitude modulation (QAM) [9] and orthogonal frequency division multiplexing (OFDM) [10], [11]. An example of such schemes is the spatial pulse position modulation (SPPM) scheme [7] which combines SSK and PPM.…”

mentioning

confidence: 99%

Effect of Synchronization Error on Optical Spatial Modulation

Olanrewaju

Popoola

2017

IEEE Trans. Commun.

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Abstract-This work examines the effect of synchronisation error on the performance of spatial modulation (SM) technique in optical wireless communication (OWC) systems. SM exploits the deployment of multiple transmitters by encoding user information on their spatial domain. In most works related to SM, a perfect synchronisation among these multiple transmitters is assumed. However, synchronisation error can result from multipath propagation in OWC channel, and clock jitter and variation in propagation delay of each transmitter. Such error in synchronisation degrades system performance and hence the need to investigate its effect. Using union bound technique, and defining synchronisation errors as timing offsets in the received signals, we derive the symbol error rate for space shift keying (SSK), generalised SSK (GSSK), SM and generalised SM (GSM) schemes, and we validate our analysis with tightly-matched simulation results. Results show degradation in performance increases with synchronisation error. While SSK is tolerant for a small range of synchronisation error, GSSK, SM and GSM are significantly impaired. Our results also demonstrate the dependence of SM on channel gain values. We observe that the lower the channel gain of the transmitter in which synchronisation error occurs, the lesser the impact of the synchronisation error on the system performance.

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Optimal Power Allocation in Spatial Modulation OFDM for Visible Light Communications

Cited by 43 publications

References 16 publications

Spatial Modulation – A Low Complexity Modulation Technique for Visible Light Communications

Spatial Modulation – A Low Complexity Modulation Technique for Visible Light Communications

Pilot symbol utilization for reducing peak-to-average power ratio in optical OFDM

Effect of Synchronization Error on Optical Spatial Modulation

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