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Identification (ID) systems utilizing visible light are an interesting topic, and have been attracting the growing attention of researchers recently. However, LED transmitters with a unique ID illuminate a limited coverage area, therefore, limiting the communication coverage. In order to extend the communication coverage, we proposed wireless mesh networks (WMNs) for relaying the information. Routing operations in WMNs might be challenging due to various factors. In this paper we analyze the link error probability and optical power loss. Based on our proposed network topology, we further found an effective scheme, multi-stage parallel interference cancellation (PIC), to alleviate the negative impacts due to interference which comes from multi-user data transmission.

Wireless technologies are an essential communication means that transform a branched localized fixed meshwork into a ubiquitous disconnected network. A clear trend shows that cells are becoming smaller, homogeneously distributed, operating at higher carrier frequencies, and more energy conscious. This points toward wireless picocell systems that implement millimeter-wave (mm-wave) modulation. In this work various techniques are proposed, which are oriented to specific traits of the 60-GHz mm-wave band. Two techniques oriented to solve physical and data-link layer issues are proposed. Single carrier frequency division multiple access (SC-FDMA) is proposed as the technology to be implemented at the physical layer, and a variable slot time multiplexing access technique, called variable slot time-time division multiple access (VST-TDMA), with a conscious energy-conservation protocol, is proposed for the data-link (MAC) layer. SC-FDMA with pulse shaping is implemented to minimize the peak-to-average power ratio of the system, which reduces energy consumption. The multiplexing access technique takes advantage of the reduced cell size by multiplexing data in the time domain, this allows the reduced number of users to utilize the entire available bandwidth. Incorporated into the access protocol is the option of energy pacing or even self-sustainability if an energy harvesting device is present. Self-sustainability can be achieved at the cost off throughput, some techniques are discussed to relieve this trade-off condition. Also, a thorough discussion is included on battery energy depletion, even with an energy harvesting device present, to further increase the through- put performance. Since using SC-FDMA reduces the energy consumption, it enables VST-TDMA to operate at higher speeds under self-sustainability mode. Overall the proposed set of solutions showed independently significant improvements to the system. It is also discussed how these techniques coalesce conveniently by working in unison, improving the energy efficiency and throughput capabilities of 60-GHz systems.Keywords 60 GHz · Energy self-sustainability · Millimeter-wave · Peak-to-average power ratio (PAPR) · Single carrier frequency division multiple access (SC-FDMA) · Variable slot time-time division multiple access (VST-TDMA)

Energy independence is a wireless device quality that demands the utmost exigency. Energy harvesting devices (EHD) alleviate the energy constraints demanded by these nodes and with the use of protocols, such as variable slot time-time division multiple access (VST-TDMA) energy self-sustainability can be attained at the cost of throughput. To allow high throughput levels and self-sustainability the system can allow the power consumption to be greater than the energy harvesting rate while a state-of-charge (SoC) of 30% or greater is maintained. To achieve this the system must accurately estimate the SoC, which is not a trivial task. In this work, a battery model is incorporated into the VST-TDMA protocol to estimate the battery model parameters, including the SoC, which successfully allows it to maintain appropriate SoC levels.

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