Tight Bounds on Channel Capacity for Dimmable Visible Light Communications

Wang, Junbo; Hu, Qiaodan; Wang, Jiangzhou; Chen, Ming; Wang, Jin‐Yuan

doi:10.1109/jlt.2013.2286088

Cited by 220 publications

(159 citation statements)

References 18 publications

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“…where 0 ≤ ξ ≤ 1 is the dimming target [5]. For the sake of analysis, we define x i xi P0 , i = 1, 2 as the normalized power transmitted from each LED.…”

Section: System Modelmentioning

confidence: 99%

“…5 Note that h ki 's are non negative and model the overall gains of the line of sight (LOS) optical path between the i th LED and the k th user and also the responsivity of the PD of the k th user [3]. 6 Note that the above noise impairments of the received signal are the main impairments that are commonly assumed in VLC systems [3].…”

Section: An Achievable Rate Region Of the Channel In (5)mentioning

confidence: 99%

“…correspond to an achievable rate pair for the broadcast channel in (5). Since a rectangle in the u 1 − u 2 plane corresponds to a unique U 1 and U 2 and vice versa, it follows that any rectangle lying inside the parallelogram R // (H) and having its midpoint at D(H, ξ) will correspond to an achievable rate pair.…”

Section: An Achievable Rate Region Of the Channel In (5)mentioning

confidence: 99%

“…The modulation symbols are also constrained to be less than a pre-determined value as the intensity of the light emitted by the LED is peak constrained due to safety regulations and also due to the limited linear range of the transfer function of LEDs [1], [3]. Moreover, due to constant lighting the mean value of the modulation symbol is also fixed (i.e., non-time varying) and can be adjusted according to the users' requirement (dimming target) [4], [5].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Achievable Rate Region of the Zero-Forcing Precoder in a $2\times 2$ MU-MISO Broadcast VLC Channel With Per-LED Peak Power Constraint and Dimming Control

Agarwal¹,

Mohammed²

2017

J. Lightwave Technol.

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Abstract-In this paper, we consider the 2 × 2 multi-user multiple-input-single-output (MU-MISO) broadcast visible light communication (VLC) channel with two light emitting diodes (LEDs) at the transmitter and a single photo diode (PD) at each of the two users. We propose an achievable rate region of the Zero-Forcing (ZF) precoder in this 2 × 2 MU-MISO VLC channel under a per-LED peak and average power constraint, where the average optical power emitted from each LED is fixed for constant lighting, but is controllable (referred to as dimming control in IEEE 802.15.7 standard on VLC). We analytically characterize the proposed rate region boundary and show that it is Pareto-optimal. Further analysis reveals that the largest rate region is achieved when the fixed per-LED average optical power is half of the allowed per-LED peak optical power. We also propose a novel transceiver architecture where the channel encoder and dimming control are separated which greatly simplifies the complexity of the transceiver. A case study of an indoor VLC channel with the proposed transceiver reveals that the achievable information rates are sensitive to the placement of the LEDs and the PDs. An interesting observation is that for a given placement of LEDs in a 5 m × 5 m × 3 m room, even with a substantial displacement of the users from their optimum placement, reduction in the achievable rates is not significant. This observation could therefore be used to define "coverage zones" within a room where the reduction in the information rates to the two users is within an acceptable tolerance limit.

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“…where 0 ≤ ξ ≤ 1 is the dimming target [5]. For the sake of analysis, we define x i xi P0 , i = 1, 2 as the normalized power transmitted from each LED.…”

Section: System Modelmentioning

confidence: 99%

Section: An Achievable Rate Region Of the Channel In (5)mentioning

confidence: 99%

Section: An Achievable Rate Region Of the Channel In (5)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Achievable Rate Region of the Zero-Forcing Precoder in a $2\times 2$ MU-MISO Broadcast VLC Channel With Per-LED Peak Power Constraint and Dimming Control

Agarwal¹,

Mohammed²

2017

J. Lightwave Technol.

View full text Add to dashboard Cite

show abstract

“…Based on the wellknown sphere packing method [7], tight closed-form upper bounds are derived in [8], [9]. However, there is an obvious gap between these upper bounds and the lower bound in high optical signal-to-noise ratios (OSNRs) region.…”

Section: Introductionmentioning

confidence: 99%

A Tight Upper Bound on Channel Capacity for Visible Light Communications

et al. 2016

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Abstract-Since the optical wireless channel in visible light communication (VLC) systems is subject to the nonnegativity of the signal and the average optical power, the classic Shannon channel capacity formula is not applicable to VLC systems. To derive a simple closed-form upper bound on channel capacity, sphere packing argument method has been applied previously. However, there is an obvious gap between the existing spherepacking upper bounds and the lower bounds at high optical signal-to-noise-ratios (OSNRs), which is mainly caused by the inaccurate mathematical approximation of the intrinsic volumes of the simplex. In this letter, a tight sphere-packing upper bound is derived with a new approximation method. Numerical results demonstrate that compared to the existing sphere-packing upper bounds, our proposed upper bound is tighter at high OSNRs.

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