Aggregate Data Rate Research Articles

Resource Allocation for Heterogeneous Applications With Device-to-Device Communication Underlaying Cellular Networks

Mobile data traffic has been experiencing a phenomenal rise in the past decade. This ever-increasing data traffic puts significant pressure on the infrastructure of state-of-the-art cellular networks. Recently, device-to-device (D2D) communication that smartly explores local wireless resources has been suggested as a complement of great potential, particularly for the popular proximity-based applications with instant data exchange between nearby users. Significant studies have been conducted on coordinating the D2D and the cellular communication paradigms that share the same licensed spectrum, commonly with an objective of maximizing the aggregated data rate. The new generation of cellular networks, however, have long supported heterogeneous networked applications, which have highly diverse quality-of-service (QoS) specifications. In this paper, we jointly consider resource allocation and power control with heterogeneous QoS requirements from the applications. We closely analyze two representative classes of applications, namely streaming-like and file-sharing-like , and develop optimized solutions to coordinate the cellular and D2D communications with the best resource sharing mode. We further extend our solution to accommodate more general application scenarios and larger system scales. Extensive simulations under realistic configurations demonstrate that our solution enables better resource utilization for heterogeneous applications with less possibility of underprovisioning or overprovisioning.

8-Gb/s RGBY LED-Based WDM VLC System Employing High-Order CAP Modulation and Hybrid Post Equalizer

In this paper, for the first time, we propose the use of a hybrid post equalizer in a high-order carrierless-amplitude-and-phase-modulation-based visible light communication (VLC) system. The hybrid equalizer consists of a linear equalizer, a Volterra-series-based nonlinear equalizer, and a decision-directed least mean squares equalizer to simultaneously mitigate the linear and nonlinear distortions of the VLC system. A commercially available red-blue-green-yellow light-emitting diode (RBGY LED) is utilized for four-wavelength multiplexing. By the hybrid equalizer, an aggregate data rate of 8 Gb/s is experimentally achieved over a 1-m indoor free-space transmission with the bit error rate (BER) below the 7% forward error correction (FEC) limit of 3.8 × 10 -3 . To the best of our knowledge, this is the highest data rate ever reported in high-speed VLC systems.

Fisheye-lens-based space division multiplexing system for visible light communications

This paper presents the high-diversity space division multiplexing (SDM) visible light communications (VLCs) utilizing a fisheye-lens-based imaging receiver. The receiver features ultra-wide field-of-view, good illumination uniformity, ultra-high imaging quality, and compact size; therefore, it can realize omnidirectional receiving and provide high spatial diversity for the SDM VLC system. In the presented system, four data streams are parallelly transmitted by commercial phosphorescent white light-emitting diodes, and discrete multitone signals based on quadrature amplitude modulation and bit loading are employed to achieve high spectral efficiency. The experiment verifies that the interchannel interference is effectively alleviated due to the high spatial diversity provided by the fisheye-lens-based receiver, and an aggregate data rate of 1.3 Gbit/s is achieved with the limited 3-dB bandwidth of 20 MHz. Besides, it is feasible to extend the system to more channels to achieve higher capacity. The experimental results indicate that the fisheye-lens-based imaging receiver is a potential candidate for high-speed VLC applications.

Energy-Aware Signal Integrity Analysis for High-Speed PCB Links

This paper proposes a novel approach to evaluate design alternatives for high-speed links on printed circuit boards. The approach combines evaluations of signal integrity and link input power. For a comprehensive analysis, different link designs are made comparable through the application of identical constraints, with the link input power as the single figure of merit for a systematic, quantitative comparison of design alternatives. The analysis relies upon a combination of efficient physics-based via and trace models, statistical time-domain simulation, and an analytical input power evaluation, which allows it to handle links consisting of a large number of channels while fully taking into account interchannel crosstalk. The proposed approach is applied to study two fundamental design decisions at the PCB level—single-ended versus differential signaling and signal-to-ground via ratios of 1:1 versus 2:1—for a link consisting of 2048 vias and up to 175 striplines with an aggregate data rate of 1 Tb/s. It is found that both design decisions have a considerable impact on the required input power of the link.

Error probability performance of a short-reach multicore fiber optical interconnect transmission system.

A standalone module for rectangular array multicore fiber (MCF)-based optical interconnect (OI) is realized that includes inherent intercore crosstalk and provides space division multiplexed coupling/decoupling of optical power. The module is integrated in a short-reach communication system to provide bit error probability (BEP). Next, a closed-form equation for BEP applicable to MCF OI with intercore crosstalk is derived. For characteristic parameters of the module, results obtained by two approaches agree within 1% for 40 Gbps per channel and predict an error-free transmission of aggregated data rate of 2.5 Tbps through the MCF OI under consideration.

Experimental Demonstration of 120-Gb/s Nyquist PAM8-SCFDE for Short-Reach Optical Communication

The limited band of optical and electrical devices in an intensity-modulation direct detection (IM/DD) system is considered to be a major bottleneck that hinders the increase in transmission capacity. Spectrally efficient modulation formats and advanced digital signal processing are key technologies to improving the performance of IM/DD for high-speed short-reach optical systems. In this paper, we propose and experimentally demonstrate a novel Nyquist eight-level, pulse-amplitude, single-carrier modulation with frequency-domain equalization (PAM8-SCFDE). In addition, 40-GBd Nyquist PAM8-SCFDE signals can be successfully transmitted over 2-km standard single-mode fiber or 20-km large effective area fiber based on 10-G-class DAC and photodiode. Therefore, the achieved aggregate data rate is 120 Gb/s, and the measured bit error rate (BER) is under 7% pre-forward-error-correction (FEC) threshold of $3.8\times 10^{-3} $ . Compared with conventional PAM8, this scheme can provide double spectral efficiency and 6-dB receiver sensitivity improvement.

μLED-Based Single-Wavelength Bi-directional POF Link With 10 Gb/s Aggregate Data Rate

We report record 10 Gb/s bi-directional data transmission over a single 10 m SI-POF, by employing blue microlight-emitting diodes (μLEDs) at a single wavelength, APD receivers, and a PAM-32 modulation scheme. The implementation of 10 Gb/s LED-POF links takes advantage of the bi-directional configuration, which doubles the overall channel capacity, and APDs, which provide an enhanced link power budget owing to their improved sensitivity compared with conventional p-i-n photodiodes. Moreover, the high spectral efficiency of the PAM-32 modulation scheme employed, together with equalization techniques, enable the full utilization of the link bandwidth and the transmission of data rates higher than those obtained with conventional on–off keying. Simulation and experimental results demonstrate the feasibility of such a bi-directional link, and simultaneous 5 Gb/s data transmission is realized in each direction, achieving an aggregate data rate of 10 Gb/s with a BER < 10−3. The crosstalk penalty between the two directions of the link is measured to be less than 0.5 dB.

Enhanced Performance of a High-Speed WDM CAP64 VLC System Employing Volterra Series-Based Nonlinear Equalizer

The light-emitting diode nonlinearity in visible light communication (VLC) systems is considered to be a major problem that deteriorates system performance. In this paper, we experimentally demonstrate a high-speed WDM CAP64 VLC system employing a Volterra series-based nonlinear equalizer to mitigate the nonlinear effect. A modified cascaded multimodulus algorithm (M-CMMA) is utilized to calculate the error function and update the weights of the nonlinear equalizer without using training symbols. An aggregate data rate of 4.5 Gb/s is successfully achieved over 2-m indoor free-space transmission with a bit error rate (BER) below the 7% forward error correction limit of 3.8 × 10 -3 . With the Volterra nonlinear equalizer, the Q factor of the VLC system is 1. 6 dB better than that without using the nonlinear equalizer, and the transmission distance is also increased by about 110 cm at the BER of 3.8 × 10 -3 . To the best of our knowledge, this is the first time that the Volterra nonlinear equalizer is utilized for high-speed carrierless amplitude and phase (CAP) modulation-based VLC systems.

Single Frequency-Based Device-to-Device-Enhanced Video Delivery for Evolved Multimedia Broadcast and Multicast Services

Despite of the undisputed benefits of the long term evolution-advanced (LTE-A) networks, offering support for group-oriented services challenges the evolved multimedia broadcast multicast services (eMBMS) design in LTE-A. This is especially important when delivering video content with high bitrate requirements. The conventional multicast scheme (CMS) is proposed as a radio resource allocation solution for eMBMS to serve all multicast group members with the data rate supported by the receiver with the worst channel conditions. In this paper, we propose a novel radio resource management approach, the device-to-device (D2D)-enhanced CMS with single frequency (D2D-SF). This proposal extends the CMS with additional D2D communications in order to increase the aggregate data rate of the cell, while also maintaining the typical CMS short-term fairness. D2D-SF makes use of one or more mobile subscriber devices as forwarding devices (FD) to retransmit the data received from the base station (BS) over direct local links to other members of the multicast group. The proposed solution supports both high-rate modulation and coding schemes on the downlink from BS to FDs, and reaches cell-edge devices (hence, experiencing worse channel conditions) through high-performing D2D links (improving this experience). Testing shows how the single frequency-based D2D CMS paradigm proposed, complemented by two novel strategies for selecting FDs, achieves significant enhancements of the overall performance when delivering video content compared to both the state-of-the-art multicast solutions and novel solutions that do not employ a single-frequency paradigm.

Theoretical Feasibility Demonstration for Over 100 GHz Electro-Optic Modulators With c-Axis Grown BaTiO &lt;sub&gt;3&lt;/sub&gt; Crystal Thin-Films

Single-channel 100 GHz and higher bandwidth external optical modulators are dramatically demanded to realize the aggregate carrier data rate of 100 Tb/s per optic-fiber in next-generation optical networks, but the current technologies used in industrial systems have never shown any feasibility to reach such high-speed operations. In this study, the feasible potential of ultrahigh bandwidths higher than 100 GHz are theoretically demonstrated for waveguide electro-optic (EO) modulators with c-axis-oriented BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> crystal thin-films. As the three dominant factors of determining the bandwidths of EO modulators, the interaction length L, the absolute refractive difference of light-wave and microwave |N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> -N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sub> | determining the velocity mismatch, and the microwave loss coefficient are investigated to realize the ultrahigh bandwidths of over 100 GHz, where L is a weight factor of both the velocity mismatch and the microwave loss. Thus, in this process, the nonlinear EO modulation effects are taken into account to determine the L values with respect to the values of EO coefficient r <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">51</sub> under a given half-wave voltage V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">π</sub> . Then, the optimal tradeoff conditions for the over 100 GHz bandwidths are obtained with the consistent relations among the interaction length, the optical loss, the electrode gap, and the overlap integral of optical and electrical fields, the refractive index difference between the optical guidedmode and the microwave. As a result, for an industrial acceptable V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">π</sub> of 5.0 V and a feasible absolute birefringence b <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eo</sub> of 0.005, at the EO coefficient r <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">51</sub> values of over 550 pm/V an optimal device in both optical rib waveguide and microwave electrode dimensions shows the illustrative results of over 100 GHz bandwidth in the believable simulations albeit both the velocity mismatch and the microwave loss are taken into account in simulations under a microwave impedance matching, which are all reachable in the real c-axis BaTiO3 crystal thin-film.

4.5-Gb/s RGB-LED based WDM visible light communication system employing CAP modulation and RLS based adaptive equalization.

Inter-symbol interference (ISI) is one of the key problems that seriously limit transmission data rate in high-speed VLC systems. To eliminate ISI and further improve the system performance, series of equalization schemes have been widely investigated. As an adaptive algorithm commonly used in wireless communication, RLS is also suitable for visible light communication due to its quick convergence and better performance. In this paper, for the first time we experimentally demonstrate a high-speed RGB-LED based WDM VLC system employing carrier-less amplitude and phase (CAP) modulation and recursive least square (RLS) based adaptive equalization. An aggregate data rate of 4.5Gb/s is successfully achieved over 1.5-m indoor free space transmission with the bit error rate (BER) below the 7% forward error correction (FEC) limit of 3.8x10(-3). To the best of our knowledge, this is the highest data rate ever achieved in RGB-LED based VLC systems.

First demonstration of OFDM ECDMA for low cost optical access networks.

We demonstrate for the first time to the best of our knowledge an analogue orthogonal frequency division multiplexing (OFDM) based electrical code division multiplexing access (ECDMA) passive optical network (PON) for next generation access applications. Advantages of the system include low cost, high capacity, and enhanced spectral efficiency. A proof-of-principle 16 QAM OFDM ECDMA PON downlink experiment is used to show the transmission of an aggregate data rate of 24.8 Gb/s within an eight-user system. Transmission is achieved over 25 km of single-mode telecommunications fiber (SMF) with negligible dispersion and crosstalk penalties.

Integrated reconfigurable microring based silicon WDM receiver for on-chip optical interconnect

We demonstrate an integrated reconfigurable wavelength division multiplexing receiver on the silicon-on-insulator (SOI) platform. The receiver is composed of a 1 × 8 thermally tunable microring resonator filter and Ge–Si photodetectors. With low thermal tuning powers the channel allocation of the receiver can be reconfigured with high accuracy and flexibility. The thermal tuning efficiency is approximately 8 mW nm−1. We show eight-channel configurations with channel spacing of 100 GHz and 50 GHz and a configuration in which all eight channels cover an entire free spectral range of the ring with uniform channel spacing of 1.2 nm. Each channel can receive high-quality signals with a data rate of up to 13.5 Gb s−1; thus an aggregate data rate higher than 100 Gb s−1 can be achieved.

A Solution to the Multicast Subgroup Formation Problem in LTE Systems

This letter proposes a solution to the multicast subgroup formation problem that aims to maximize the aggregate data rate in Long Term Evolution (LTE) and beyond systems. We analytically demonstrate that, by reducing the solution search space and releasing some constraints, the problem can be solved in a closed form, and a very small number of operations are sufficient to find the optimal subgroup configuration, which is demonstrated to be always composed of one or two subgroups. The relevance of the result is that the proposed technique can be easily implemented in practical LTE systems to avoid the heavy-processing burden of the exhaustive search or the suboptimality of solutions based on heuristics.

A Power-Harvesting Pad-Less Millimeter-Sized Radio

A wireless-powered pad-less single-chip radio is implemented in 65 nm CMOS for applications in Internet of Things (IoT) and wireless tagging. This fully-self-sufficient mm-wave radio has no pads or external components (e.g., power supply), and the entire radio is a single chip with dimensions of 3.7 mm by 1.2 mm. To provide multi-access, and to mitigate interference, it uses two separate mm-wave bands for RX/TX and integrates both antennas to provide a measured communication range of 50 cm. The transmitter uses a modified Multipulse Pulse Position Modulation (MPPM) with 2 GHz of bandwidth on a 60 GHz carrier to communicate the data sequence as well as the local timing reference. The entire system operates with standby harvested power below 1.5 µW and achieves an aggregate data rate > 12 Mbps.

Not Every Bit Counts

Many applications involving machine-to-machine (M2M) communications are characterized by the large amount of data to transport. To support these M2M applications, we argue in this article that instead of focusing on serving individual machines with better quality, one should focus on solutions that can better serve the data itself. To substantiate, we consider the application of data gathering from a set of machines that communicate directly to an aggregator. Since the aggregator has limited radio resources, the problem arises as to how the resource can be effectively utilized for supporting such an application. We investigate “data-centric” resource allocation that aims to maximize information entropy of data collected through selecting the subset of machines to transmit, determining the amount of resources to allocate, and scheduling the sequence of transmissions. We present two instantiations of the problems when machines can perform distributed source coding or dependent source coding based on the data overheard from neighboring machines and then propose algorithms for solving the joint optimization problems. Evaluation results show that compared to conventional “machine-centric” resource allocation that aims to maximize the aggregate data rates or number of supported machines, “data-centric” resource allocation exhibits significant performance gain in terms of the quality of data that can be collected for the given amount of radio resources.

Experimental verification of performance improvement for a gigabit wavelength division multiplexing visible light communication system utilizing asymmetrically clipped optical orthogonal frequency division multiplexing

Asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) has been a promising candidate in visible light communications (VLC) due to its improvement in power efficiency and reduction of nonlinearity based on previous simulation analysis. In this paper, for the first time as far as we know, we experimentally verify that ACO-OFDM would be an efficient scheme to improve the performance of a gigabit wavelength division multiplexing VLC system. Our theoretical investigations reveal that the advantages of ACO-OFDM can be attributed to the reduction of inter-carrier interference caused by signal–signal beating noise. An aggregate data rate of 1.05 Gb/s is successfully achieved over 30 cm transmission below the 7% forward-error-correction threshold of 3.8×10−3. The experimental results show that ACO-OFDM can outperform DC-biased optical OFDM by BER performance of 1.5 dB at the same data rate and 4 dB at the same bandwidth, which clearly demonstrates the benefit and feasibility of ACO-OFDM.

Silicon Parallel Single Mode 48 × 50 Gb/s Modulator and Photodetector Array

We report a silicon nanophotonic parallel single mode transmitter and receiver with an aggregate data rate of 2.4 Tb/s. The transceiver is composed of 48 channels, each operating at 50 Gb/s. Bit error rate versus power measurements demonstrate that each transmitter channel is capable of operating at a BER of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-9</sup> . The receiver is shown to provide open eyes at 50 Gb/s. Furthermore, insertion loss and sensitivity data of the transmitter show uniformity within 3 dB across all 48 channels.

Path loss prediction models for Corridor propagation at 24GHz

Mm-wave bands have recently become major options for short-range, high speed communication systems especially in the indoor wireless local area networks (WLANs). The pathloss prediction model is one of the metric parameters for determining the system effectiveness and performance in wireless indoor propagation. The channel characterization of 24GHz band in corridor propagation through extensive field strength measurements in real time application was conducted in this work. The results were used to derive the path loss equation for corridor propagation at this spectrum band based on log-distance path loss model and log-normal shadowing model. The pathloss realized falls within the estimated values in such scenario, it is therefore concluded that the predicted mathematical model for the described environment is accurate. Also the predicted pathloss which is lower than the free space propagation path loss results in aggregate high data rate, hence improved system performance is achieved.

A Coalitional Game-Based Algorithm for OFDMA Resource Allocation in Multicast Cognitive Radio Networks

This letter investigates resource allocation for orthogonal frequency division multiple access (OFDMA)-based multicast cognitive radio networks (MCRNs) under the consideration of primary users' activities. Due to the heterogeneity of channel gains among secondary users (SUs), the existing multicast schemes are highly conservative and spectrally inefficient. To address this issue, we formulate a novel multicasting problem for MCRNs. This new formulation optimally and adaptively exploits multiuser diversity of OFDMA through dynamic group formation, which clusters SUs within a multicast group into multiple smaller subgroups (coalitions) based on their channel gains. Subcarriers and power are then allocated to these subgroups to maximize aggregate data rate (ADR) of the system. A coalitional game theory is adopted to model the group formation where SUs are allowed to form coalitions to compete for resources. A novel cognitive multicast coalitional game (CMCG) is proposed for SUs to self-organize to reach multi-coalitional equilibrium where optimality can be obtained. Simulation results show that the proposed CMCG algorithm significantly improves the system ADR as compared to the conventional unicast and multicast schemes.