Multicarrier communication with variable overhead rate

Abstract

In the present invention, the overhead data transmission rate in a multicarrier communication system (1) may be changed and / or selected. More specifically, this rate may be selected during an initial negotiation process and / or during a steady state mode of operation.

Description

[0001] The subject application claims the priority of U.S. Provisional Patent Application Serial No. 60 / 090,891, filed Jun. 26, 1998, entitled "Multicarrier Modem with Variable Overhead Rate." The disclosure of said Provisional Application is incorporated herein by reference in its entirety.[0002] 1. Field of the Invention[0003] This invention relates generally to communications, and more particularly, to a multicarrier communications system and method that are able to controllably change an overhead channel data transmission rate.[0004] 2. Brief Description of Related Prior Art[0005] The public switched telephone network (PSTN) provides the most widely available form of electronic communication for most individuals and businesses. Because of its ready availability and the substantial cost of providing alternative facilities, it is increasingly being called upon to accommodate the expanding demands for transmission of substantial amounts of data at high rates. Structured originally ...

AI Technical Summary

Benefits of technology

[0021] In one embodiment, the system of the present invention may comprise two DMT DSL modems, one located at a customer premises and another located at a telephone central office, connected by a conventional POTS line through which the modems communicate by transmitting and receiving discrete frames and superframes of data. Within each superframe are 68 data frames and a synchronization symbol. Within each frame is a number of bytes that are allocated to payload and overhead data. The allocation of the bytes to either overhead or payload data is flexible (i.e., changeable and / or selectable). Whereas in the prior art, the first byte in each frame is dedicated to overhead data regardless of whether there is a need to transport overhead data or not, in this embodiment of the present invention, the overhead data transmission rate is determined during start-up and can be modified during steady state mode. Due to the construction of frames in DSL systems, decreasing the overhead data transmission rate during steady state mode results in a higher payload data transmission rate, while conversely, increasing the overhead data transmission rate during steady state mode results in a lower payload data transmission rate.

[0024] Similarly, in this embodiment of the present invention, it is possible to select which of the superframes are to carry overhead data-containing frames. This introduces another degree of freedom in allocating the overhead and payload data transmission rates.

Problems solved by technology

This is a marked departure from conventional DSL systems wherein the amount of throughput that is dedicated to overhead data is unchangeably fixed at 32 kbps.

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