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Transmission psd caps in packet-based ofdm systems

A technology of upper limit value and noise component, applied in the field of communication systems, which can solve the problems of performance degradation at the receiver, ADC/DAC noise trouble, and increased system complexity.

Inactive Publication Date: 2016-02-10
APPLIED TRANSFORM
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the PSD mask is not constant over the shared frequency band, in other words, the maximum allowed transmit PSD value is different for at least two subcarriers, and the difference between the lowest and highest mask levels is sufficiently large, then the system requires high dynamic range Analog-to-digital converter (ADC) or digital-to-analog converter (DAC) (which increases system complexity) or suffers from high ADC / DAC noise (which causes performance degradation at the receiver)

Method used

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  • Transmission psd caps in packet-based ofdm systems
  • Transmission psd caps in packet-based ofdm systems
  • Transmission psd caps in packet-based ofdm systems

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Embodiment Construction

[0052] Example embodiments of the invention will be described with respect to OFDM communication systems and protocols, techniques and methods for adjusting transmission power spectral density. However, it should be understood that, in general, the systems and methods of the present invention function equally well for other types of communication environments.

[0053] Example systems of the present invention will also be described with respect to multi-carrier modems, such as power line modems, coaxial cable modems, telephone line modems (such as xDSL modems and vDSL modems), and wireless modems, and associated communication hardware, software, and communication channels and methods. To avoid unnecessarily obscuring the present invention, however, the following description acknowledges well-known structures and devices that may be shown in block diagram form or otherwise outlined or known.

[0054] For purposes of explanation, numerous details are set forth in order to provi...

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Abstract

The adjusted maximum transmit PSD level has an effect on the SNR. If the ADC noise is assumed to be the limiting factor, reducing the maximum transmit PSD level may be beneficial. For example, reducing the maximum transmit PSD level from -50dBm / Hz to -70dBm / Hz results in an increase in SNR for subcarriers above 30MHz. The SNR of subcarriers above 30MHz can be increased from 30db(-80-(-110)) to 50db(-80-(-130)). Thus, by varying the maximum transmit PSD level, imposing an upper bound on the PSD mask, the sum of available SNRs over the available subcarriers is increased, thus increasing the achievable OFDM data rate. In other words, the maximum transmit PSD mask may be used to reduce the transmit PSD value of at least one subcarrier, which results in an increased SNR of at least one subcarrier.

Description

[0001] related application [0002] This application claims the benefit of and priority under 35 U.S.C. § 119(e) to U.S. Patent Application Serial No. 61 / 091,615, filed August 25, 2008, entitled "Maximum Transmit PSDA Adjustment in Packet-Based OFDM Systems," which is incorporated by reference in its entirety Incorporated into this article. technical field [0003] Example aspects of the invention relate to communication systems. More specifically, example aspects of the invention relate to communication systems that exchange information using packet-based transmission based on Orthogonal Frequency Division Multiplexing (OFDM), also known as multi-carrier modulation. More specifically, example aspects of the invention relate to when there are multiple maximum allowable transmit PSD levels within a power spectral density (PSD) mask defined on a shared channel (where multiple users communicate with each other using packet-based transmission based on OFDM). Usually adjust the ...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L5/00
CPCH04L5/0007H04L5/0037H04L5/006H04L5/0091
Inventor 金俊培马科斯·T·扎尼斯皮特·尼尔斯·赫勒斯图尔特·桑德伯格
Owner APPLIED TRANSFORM