Channel equalization for indoor lighting communications networks

We consider indoors communications networks using modulated LEDs to transmit the information packets. A generic indoor channel equalization formulation is proposed assuming the existence of both line of sight and diffuse emitters. The proposed approach is of relevance to emergent indoors distributed sensing modalities for which various lighting based network communications protocols are considered

Constrained pre-equalization accounting for multi-path fading emulated using large RC networks: applications to wireless and photonics communications

Multi-path propagation is modelled assuming a multi-layer RC network with randomly allocated resistors and capacitors to represent the transmission medium. Due to frequency-selective attenuation, the waveforms associated with each propagation path incur path-dependent distortion. A pre-equalization procedure that takes into account the capabilities of the transmission source as well as the transmission properties of the medium is developed. The problem is cast within a Mixed Integer Linear Programming optimization framework that uses the developed nominal RC network model, with the excitation waveform customized to optimize signal fidelity from the transmitter to the receiver. The objective is to match a Gaussian pulse input accounting for frequency regions where there would be pronounced fading. Simulations are carried out with different network realizations in order to evaluate the sensitivity of the solution with respect to changes in the transmission medium mimicking the multi-path propagation. The proposed approach is of relevance where equalization techniques are difficult to implement. Applications are discussed within the context of emergent communication modalities across the EM spectrum such as light percolation as well as emergent indoor communications assuming various modulation protocols or UWB schemes as well as within the context of space division multiplexing

Using full duplex relaying in device-to-device (D2D) based wireless multicast services: a two-user case

D2D communication has been proposed as an important supplement to the existing centralized cellular networks which allows two physically adjacent cellular user equipments (UEs) to communicate directly. This paper concerns using D2D to improve wireless multicast services in cellular networks. Specially, we consider a D2D transmitter UE can act as a full-duplex (FD) relay to assist a cellular multicast from a base station (BS) to a group of two UEs. And a new scheme which allows an intra-cell D2D retransmission to underlay a cellular multicast is proposed. Under the constraint of the minimum signal-to-interference-and-noise ratio (SINR) required by each of the receiver UEs, the aim of the scheme is to select the best UE in a multicast group to perform the D2D retransmission with the serving BS. Thus, the aggregate transmit power consumed at the BS and at the selected UE can be minimized. The numerical results show that the proposed scheme outperforms traditional cellular multicast scheme as it consumes less transmit power to achieve the same SINR target at the receiver UEs