Bandwidth (signal processing)

About: Bandwidth (signal processing) is a research topic. Over the lifetime, 48550 publications have been published within this topic receiving 600741 citations. The topic is also known as: Bandwidth (signal processing) & bandwidth.

Multi-Wideband Waveform Design for Distance-Adaptive Wireless Communications in the Terahertz Band

Abstract: Terahertz band communication is envisioned as a key technology to satisfy the increasing demand for ultra-high-speed wireless links. In this paper, a multi-wideband waveform design for the THz band is proposed, by exploiting the channel peculiarities including the distance-varying spectral windows, the delay spread and the temporal broadening effects. This scheme allows the dynamical variation of the rate and the transmit power on each sub-window and improves the distance. Moreover, the closed-form expressions of the signal-to-interference-plus-the-noise and bit-error-rate for the multi-wideband waveform are derived, by considering the inter-symbol and inter-band interferences. Then, an optimization framework is formulated to solve for the multi-wideband waveform design parameters of the transmit power and the number of frames, with the aim to maximize the communication distance while satisfying the rate and the transmit power constraints. Four sub-optimal solutions are proposed and compared. The results show that the SINR increases with the transmit power and the number of frames, at the cost of the power consumption and the rate decrease. With the transmit power of 10 dBm, the largest distance to support 10 Gbps for the multi-path propagation is 4 m, which is realized via the power allocation scheme to minimize the power/bit on each sub-window and is 10% improvement over the fixed scheme. However, for the directional transmission, this scheme under-exploits the transmit power severely. Instead, the allocation scheme that minimizes the number of frames outperforms the other three schemes. In terms of the maximum distance that achieves 30 Gbps, this scheme reaches 22.5 m.

100G and beyond with digital coherent signal processing

Abstract: The demand for increased bandwidth is ever present. Coherent technology coupled with advanced modulation formats and digital signal processing is a key enabler for optical communication systems at 100 Gb/s and beyond. This article reviews the attributes of coherent systems in light of the challenges faced by system designers to realize increased bit rates for next-generation optical systems.

Joint Optimal Cooperative Sensing and Resource Allocation in Multichannel Cognitive Radio Networks

Abstract: In this paper, the problem of joint multichannel cooperative sensing and resource allocation is investigated. A cognitive radio network with multiple potential channels and multiple secondary users is considered. Each secondary user carries out wideband spectrum sensing to get a test statistic for each channel and transmits the test statistic to a coordinator. After collecting all the test statistics from secondary users, the coordinator makes the estimation as to whether primary users are idle or not in the channels. When a channel is estimated to be free, secondary users can get access to the channel with assigned bandwidth and power. An optimization problem is formulated, which maximizes the weighted sum of secondary users' throughputs while guaranteeing a certain level of protection for the activities of primary users. Although the problem is nonconvex, it is shown that the problem can be solved by bilevel optimization and monotonic programming. This paper is also extended to cases with consideration of proportional and max-min fairness.

RF spectrum analysis of optical signals using nonlinear optics

Abstract: We study a technique to measure the radio-frequency (RF) spectrum of an optical signal based on nonlinear optics. The conventional approach, based on fast photodetection and analysis of the generated photocurrent via electronics means, is replaced by a nonlinear interaction of the source under test with a quasimonochromatic source followed by an optical spectrum measurement. Our technique has the advantage of an all-optical measurement that can provide a much larger bandwidth than electronic alternatives. The properties of this diagnostic, such as resolution and bandwidth, are studied. Typical applications to the monitoring of optical signals are presented.

Control and data signaling in heterogeneous wireless communication networks

Abstract: A method in a wireless communication device including receiving control signaling from a base station in a control region of a downlink carrier spanning a first bandwidth, receiving a signaling message from the base station indicating a second bandwidth, receiving a first control message within the control region using a first Downlink Control Information (DCI) format size, the first DCI format size based on the first bandwidth, and receiving a second control message within the control region using a second DCI format size, the second DCI format size based on the second bandwidth, wherein the second bandwidth is distinct from the first bandwidth and the first and second control messages indicate downlink resource assignments for the downlink carrier.