Abstract:
The design of a programmable receiver for an ultra wideband (UWB) communication is presented. The receiver is using a fast analog to digital converter (ADC) and a field programmable gate array (FPGA) allowing a rapid performance evaluation for various system architectures and signal processing algorithms. To demonstrate the performance and the versatility of the receiver, a simple communication system and a localization system are implemented. The accuracy of the latter is presented for an indoor environment. 1. Introduction With the recent progresses in digital electronics, the concept of the software defined radio (SDR) has gained a lot of interest for rapid development and prototyping of communication systems. A versatile SDR for wideband signaling without an application specific analog front-end requires a high sampling rate. In consequence, the specifications for the ADC and the digital signal processing units are tight. The presented receiver uses an FPGA for the signal processing, because it provides a well-balanced ratio between its available processing power and its reconfigurability. Although platforms with an ADC and an FPGA are commercially available up to several gigasamples per second, we have developed a custom programmable receiver to fit our needs. Among others they include the availability of an accurate, tunable quartz clock, the option to synchronize several programmable receivers, and a convenient mean for the data exchange with a personal computer (PC). In Section 2, the hardware and the software of the platform is presented considering the example of a communication system. In Section 3, the versatility of the programmable receiver is demonstrated for an indoor localization system. Finally, some concluding remarks are given in Section 4. 2. Communication System In this section, a noncoherent receiver for an impulse radio (IR) communication system is presented. A mathematical description of the IR is followed by a description of the hardware of the transmitter and the receiver. Then, the algorithms are presented. The communication system has a low complexity and applies to applications with a restricted data rate using a pulse delay modulation. 2.1. Signaling and Modulation Impulse radio is one flavor of UWB and is based on the transmission of short-duration pulses ？？(？？). Among others, the information to be transmitted can be used to modulate the amplitude, the polarity, or a delay of the pulses. In the following, a time hopping (TH) signaling scheme is considered, where each transmitter is attributed an unambiguous spreading code

Abstract:
In this paper, we present an analytical model for a diffusive molecular communication (MC) system with a reversible adsorption receiver in a fluid environment. The time-varying spatial distribution of the information molecules under the reversible adsorption and desorption reaction at the surface of a bio-receiver is analytically characterized. Based on the spatial distribution, we derive the number of newly-adsorbed information molecules expected in any time duration. Importantly, we present a simulation framework for the proposed model that accounts for the diffusion and reversible reaction. Simulation results show the accuracy of our derived expressions, and demonstrate the positive effect of the adsorption rate and the negative effect of the desorption rate on the net number of newly-adsorbed information molecules expected. Moreover, our analytical results simplify to the special case of an absorbing receiver.

Abstract:
This paper studies the mitigation of intersymbol interference in a diffusive molecular communication system using enzymes that freely diffuse in the propagation environment. The enzymes form reaction intermediates with information molecules and then degrade them so that they cannot interfere with future transmissions. A lower bound expression on the expected number of molecules measured at the receiver is derived. A simple binary receiver detection scheme is proposed where the number of observed molecules is sampled at the time when the maximum number of molecules is expected. Insight is also provided into the selection of an appropriate bit interval. The expected bit error probability is derived as a function of the current and all previously transmitted bits. Simulation results show the accuracy of the bit error probability expression and the improvement in communication performance by having active enzymes present.

Abstract:
Recently, a tabletop molecular communication platform has been developed for transmitting short text messages across a room. The end-to-end system impulse response for this platform does not follow previously published theoretical works because of imperfect receiver, transmitter, and turbulent flows. Moreover, it is observed that this platform resembles a nonlinear system, which makes the rich body of theoretical work that has been developed by communication engineers not applicable to this platform. In this work, we first introduce corrections to the previous theoretical models of the end-to-end system impulse response based on the observed data from experimentation. Using the corrected impulse response models, we then formulate the nonlinearity of the system as noise and show that through simplifying assumptions it can be represented as Gaussian noise. Through formulating the system's nonlinearity as the output a linear system corrupted by noise, the rich toolbox of mathematical models of communication systems, most of which are based on linearity assumption, can be applied to this platform.

Abstract:
The paper presents the design, simulation and construction results of the wavelength division multiplex (WDM) optical hybrid receiver module for the passive optical network (PON). The optical WDM receiver was constructed using system of three micromodules in the new circle topology. The optical micromodule contains multimode fiber pigtail 50/125 μm, VHGT filter with collimation lens and two microwave optoelectronics receiver micromodules (OE receiver micromodules). OE receiver micromodules were designed by use small signal equivalent electrical circuit model and noise model, from which the mathematically solved the transmittance function, which was used for calculation and simulation of the optimal frequency characteristics and signal to noise ratio. For determine the limit frequency of OE receiver micromodule, the transcendent equation with transmittance function was numerically solved. OE receiver micromodule was composed of decollimation lenses and microwave optoelectronics receivers with bandwidth 2,5 GHz and alternatively in SMD technology with bandwidth 1,25 GHz, using the thin layer hybrid technology. WDM receiver use radiation 1490 nm for internet and 1550 nm for digital TV signals download information.

Abstract:
In this paper, we consider the diffusive molecular communication channel between a transmitter nano-machine and a receiver nano-machine in a fluid environment. The information molecules released by the transmitter nano-machine into the environment can degrade in the channel via a first-order degradation reaction and those that reach the receiver nano-machine can participate in a reversible bimolecular-reaction with receiver receptor proteins. We derive a closed-form analytical expression for the expected received signal at the receiver, i.e., the expected number of activated receptors on the surface of the receiver. The accuracy of the derived analytical result is verified with a Brownian motion particle-based simulation of the environment.

Abstract:
In this paper, we perform receiver design for a diffusive molecular communication environment. Our model includes flow in any direction, sources of information molecules in addition to the transmitter, and enzymes in the propagation environment to mitigate intersymbol interference. We characterize the mutual information between receiver observations to show how often independent observations can be made. We derive the maximum likelihood sequence detector to provide a lower bound on the bit error probability. We propose the family of weighted sum detectors for more practical implementation and derive their expected bit error probability. Under certain conditions, the performance of the optimal weighted sum detector is shown to be equivalent to a matched filter. Receiver simulation results show the tradeoff in detector complexity versus achievable bit error probability, and that a slow flow in any direction can improve the performance of a weighted sum detector.

Abstract:
In a molecular communication network, transmitters and receivers communicate by using signalling molecules. At the receivers, the signalling molecules react, via a chain of chemical reactions, to produce output molecules. The counts of output molecules over time is considered to be the output signal of the receiver. This output signal is used to detect the presence of signalling molecules at the receiver. The output signal is noisy due to the stochastic nature of diffusion and chemical reactions. The aim of this paper is to characterise the properties of the output signals for two types of receivers, which are based on two different types of reaction mechanisms. We derive analytical expressions for the mean, variance and frequency properties of these two types of receivers. These expressions allow us to study the properties of these two types of receivers. In addition, our model allows us to study the effect of the diffusibility of the receiver membrane on the performance of the receivers.

Abstract:
The application of HTSC (high temperature superconductor) microwave devices in a UHF digital trunking communication system is introduced. The replacement between the HTSC microwave devices and the normal microwave devices is conducted. The digital sensitivity of the base station in complex electromagnetic environment has been increased to 6 dB, as the results of the experiment indicated, and this means that the coverage radius of the base station has been improved about twice, that is to say, the coverage area can be extended to four times as large as that of the current method.

Abstract:
We continue the study of communication cost of computing functions when inputs are distributed among $k$ processors, each of which is located at one vertex of a network/graph called a terminal. Every other node of the network also has a processor, with no input. The communication is point-to-point and the cost is the total number of bits exchanged by the protocol, in the worst case, on all edges. Chattopadhyay, Radhakrishnan and Rudra (FOCS'14) recently initiated a study of the effect of topology of the network on the total communication cost using tools from $L_1$ embeddings. Their techniques provided tight bounds for simple functions like Element-Distinctness (ED), which depend on the 1-median of the graph. This work addresses two other kinds of natural functions. We show that for a large class of natural functions like Set-Disjointness the communication cost is essentially $n$ times the cost of the optimal Steiner tree connecting the terminals. Further, we show for natural composed functions like $\text{ED} \circ \text{XOR}$ and $\text{XOR} \circ \text{ED}$, the naive protocols suggested by their definition is optimal for general networks. Interestingly, the bounds for these functions depend on more involved topological parameters that are a combination of Steiner tree and 1-median costs. To obtain our results, we use some new tools in addition to ones used in Chattopadhyay et. al. These include (i) viewing the communication constraints via a linear program; (ii) using tools from the theory of tree embeddings to prove topology sensitive direct sum results that handle the case of composed functions and (iii) representing the communication constraints of certain problems as a family of collection of multiway cuts, where each multiway cut simulates the hardness of computing the function on the star topology.