Data Rate Adjustment Research Articles

Flexible transceiver for an access network: a multicarrier entropy loading approach

To cope with the extraordinary bandwidth demand, an optical access network based on point-to-multipoint (P2MP) topology has been widely applied. Recently, flexible transceivers have been investigated to maximize the optical power budget of optical network units for increasing the capacity of passive optical networks. In this work, we experimentally demonstrate a low-cost, high-bandwidth P2MP solution based on multicarrier modulations and probabilistic constellation shaping technology by reusing a 10G class directly modulated laser and avalanche photodetector for the first time to our knowledge. The proposed P2MP solution is capable of achieving fine granularity data rate adjustment from 12.5 Gb/s up to 63 Gb/s. We discuss the hardware implementation aspect of the proposed multicarrier entropy loading flexible transceiver. By means of a real-time transmission experiment, we show that the proposed P2MP solution can achieve a 29 dB power budget at a symmetric 53 Gb/s line rate, which makes it well positioned to support non-residential P2MP applications such as passive optical local area networks and fiber-to-the-office.

Based on Fuzzy Measure Algorithm Message Adaptive Rate Algorithm of Internet of Things

In order to solve the problem that the existing LoRaWAN adaptive data rate control algorithm leads to low data transmission efficiency in the case of network congestion, a method combining a fuzzy logistic regression classifier and an improved adaptive data rate controller adjusting the avoidance time was proposed. The classifier could obtain the predicted congestion state by logistic regression learning. The data rate controller determined the data rate adjustment scheme according to the predicted congestion state. The experimental results showed that when the network congestion occurred in about 12s, the number of packet loss by the LoRaWAN default method was higher than that by the method in the research. The value of ADR_ MSG_CNT of the 15 source nodes in the method was 30 within 0–10 s, while the RCV_ACK_CNT of some nodes was 0. It proved that the method was more efficient than the original LoRaWAN adaptive data rate control algorithm.

Turning Waste into Wealth: Free Control Message Transmissions in Indoor WiFi Networks

A practical WiFi system only achieves a discrete data rate adjustment due to hardware constraints while channel signal-to-noise ratio (SNR) is continuous. This mismatch leads to the SNR gaps. In this paper, we introduce a novel communication mechanism, CoS ( Co mmunication through S ilent subcarriers), which turns the wasted SNR gaps into new opportunities for transmitting control messages for free. Compared with traditional piggybacking schemes, CoS is more reliable to transmit control messages from one node to many nodes. In CoS, silent subcarriers are inserted into data packets and the intervals between adjacent silent subcarriers are utilized to encode information. Since the wasted SNR gap results in under-utilization of the channel code, the data bit errors induced by silent subcarriers are corrected by the correcting capability of the existing channel code as long as we carefully design the total number of inserted silent subcarriers. Based on CoS, we design CoS-MAC to validate the effectiveness of CoS. We measure the throughput of free control messages achieved by CoS under various channel conditions and conduct simulations to show the throughput gain achieved by CoS-MAC over the existing schemes.

Enhanced Quality of Adaptive Video Streaming in HTTP-Based Protocol Using FESTIVE

For altering the network prerequisites most of the video participants fully relies upon logic i;e data rate adjustment which will modify data rate. In this paper there are three key things to do when in contrast to previous measurements i;e efficiency, fairness, stability. There is a problem known as bottleneck link which is identified when multiple data rate adaptive players watch a video. we have also mentioned about bitrate adaptation approach and three essential factors speed of transmission range, data rate choice and the process of chunk distribution. By this, everyone can discover the troubles of various countless negative interactions that occur as an effect of protecting the bitrate adaptation over HTTP. Based on appreciation of these techniques, we guide how to balance between fairness, stability and effectivity that will lead to robust video adaptation.

Water‐filling technique‐based proportionally fair scheduling algorithm for SC‐FDMA

ABSTRACTSingle carrier frequency division multiple access (SC‐FDMA) regulates that subchannels allocated to a user should be contiguous in frequency domain (i.e., contiguity constraint). Due to the constraint, the proportionally fair (PF) scheduling in SC‐FDMA is known to be non‐deterministic polynomial‐time (NP) hard. In this paper, a novel PF scheduling algorithm is proposed based on the water‐filling (WF) technique to effectively solve PF scheduling in SC‐FDMA. The proposed algorithm is composed of 2 phases: subchannel allocation and data rate adjustment phases. In the subchannel allocation phase, user's power is allocated to frequency‐contiguous subchannels for maximizing users' data rates based on the WF technique. In the data rate adjustment phase, the modulation and coding scheme of user is decided by solving the PF scheduling problem with the WF technique. Through simulations, it is shown that the proposed scheme achieves total data rates and logarithmic sum of average user data rates close to those of the optimal PF scheduling. In addition, the proposed scheme performs better than coherence subband based resource allocation scheme.

SSIM-based error-resilient cross-layer optimization for wireless video streaming

The traditional Sum of Squared Error (SSE)-based cross-layer optimization has been shown to be an effective way to improve the quality of service for wireless video streaming. However, recent research works show that the SSE-based optimization metric does not always provide the video distortion measurement that matches well with the video quality degradation observed by the human vision system. Taking advantage of the Structural SIMilarity (SSIM) metric in measuring the video perceptual quality, a SSIM-based error-resilient cross-layer optimization scheme is proposed to improve the perceptual quality for the real-time wireless video streaming in this paper. Besides the video data rate adjustment and the link adaption including the Modulation and Coding Scheme (MCS) selection, the error-resilient Rate-Distortion Optimization (RDO) for each encoding unit is introduced into the cross-layer optimization process to ensure that the video data are transmitted efficiently and reliably over the time-varying wireless channel. In addition, to ensure that cross-layer optimization scheme is more practical, a low-complexity optimal parameter selection algorithm that exploits the MCS-SNR relationship and the Rate-Quantization (R-Q) model is proposed. Experimental results show that significant performance improvements in terms of the perceptual video quality and the computational complexity are achieved for the proposed cross-layer optimization scheme.

DETECTING AND EFFECTIVE ROUTING OF TIME CRITICAL EVENTS USING CONGESTION AND DELAY AWARE ROUTING IN WSNS

Reliability and timeliness are two essential requirements of successful detection of critical events n Wireless Sensor Networks (WSNs). The base station (BS) is particularly interested about reliable and timely collection of data sent by the nodes close to the ongoing event, and at that time, the data sent by other nodes have little importance. In this paper, we modify Congestion and Delay Aware Routing (CODAR) protocol that tries to route data to the multiple sinks in congestion and delay aware manners. In this case every sensor communicates with the closest sink. If congestion occurs, it also mitigates congestion by utilizing an accurate data-rate adjustment. Each node collects control information from neighbours and works in a distributed manner. Experimental results show that modified CODAR protocol is capable of avoiding and mitigating congestion effectively, and performs better than similar known techniques in terms of reliable and timely event detection.

Adaptive upstream rate adjustment by RSOA-ONU depending on different injection power of seeding light in standard-reach and long-reach PON systems

The wavelength division multiplexing-time division multiplexing (WDM-TDM) passive optical network (PON) using reflective semiconductor optical amplifier (RSOA)-based colorless optical networking units (ONUs) is considered as a promising candidate for the realization of fiber-to-the-home (FTTH). And this architecture is actively considered by Industrial Technology Research Institute (ITRI) for the realization of FTTH in Taiwan. However, different fiber distances and optical components would introduce different power budgets to different ONUs in the PON. Besides, due to the aging of optical transmitter (Tx), the power decay of the distributed optical carrier from the central office (CO) could also reduce the injection power into each ONU. The situation will be more severe in the long-reach (LR) PON, which is considered as an option for the future access. In this work, we investigate a WDM-TDM PON using RSOA-based ONU for upstream data rate adjustment depending on different continuous wave (CW) injection powers. Both standard-reach (25km) and LR (100km) transmissions are evaluated. Moreover, a detail analysis of the upstream signal bit-error rate (BER) performances at different injection powers, upstream data rates, PON split-ratios under stand-reach and long-reach is presented.

Compensation of power drops in reflective semiconductor optical amplifier–based passive optical network with upstream data rate adjustment

In a wavelength division multiplexed-passive optical network (WDM-PON), different fiber lengths and optical components would introduce different power budgets to different optical networking units (ONUs). Besides, the power decay of the distributed optical carrier from the optical line terminal owing to aging of the optical transmitter could also reduce the injected power into the ONU. In this work, we propose and demonstrate a carrier distributed WDM-PON using a reflective semiconductor optical amplifier-based ONU that can adjust its upstream data rate to accommodate different injected optical powers. The WDM-PON is evaluated at standard-reach (25 km) and long-reach (100 km). Bit-error rate measurements at different injected optical powers and transmission lengths show that by adjusting the upstream data rate of the system (622 Mb/s, 1.25 and 2.5 Gb/s), error-free (<10−9) operation can still be achieved when the power budget drops.