Systems and methods for selecting a spectral segment for a downlink transmission
AssigneeCable Television Laboratories, Inc.
InventorsKarthik Sundaresan, Jingjie Zhu
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Abstract
The present disclosure generally relates to systems, methods and software for selecting a spectral segment for important downlink and/or uplink transmissions. Particularly, the spectral segment may be a set of contiguous subcarriers within a plurality of subcarriers transmitting over a channel to a population of cable modems. In an embodiment, the systems, methods and software disclosed herein optimize placement of a physical link channel (PLC) within an OFDM channel. In an embodiment, the system, methods and software disclosed herein optimize placement of a ranging region within an OFDMA channel.
Claims14
A method for selecting a segment within a plurality of subcarriers for a transmission over a channel to/from a population of cable modems, the method comprising:
- generating a least-common-denominator profile of maximum bit-loading values for the population of cable modems over a range of subcarriers;
- identifying segments of contiguous subcarriers within the least-common-denominator profile having the same bit-loading value;
- and
- selecting one of the segments for a transmission by:
- (i) choosing the segment with the highest bit-loading value and the widest range, when the width of the segment is equal to or greater than a target width;
- (ii) when no segments have a width equal to or greater than a target width, theoretically combining the segment having the highest bit-loading value with its immediate neighbor segment having a next highest bit-loading value to create a combined segment having a combined width at the next highest bit-loading value, then choosing the combined segment when the combined width is equal to or greater than the target width;
- or
- (iii) repeating step (ii) until a combined segment with the target width is created.
A non-transitory computer-readable medium having a plurality of non-transitory instructions executable with a processor for selecting a segment within a plurality of subcarriers for a transmission over a channel to a population of cable modems, the plurality of non-transitory instructions being executable for:
- generating a least-common-denominator profile of maximum bit-loading values for the population of cable modems over a range of subcarriers;
- identifying segments of contiguous subcarriers within the least-common-denominator profile having the same bit-loading value;
- and
- selecting one of the segments for a transmission by:
- (i) choosing the segment with the highest bit-loading value and the widest range, when the width of the segment is equal to or greater than a target width;
- (ii) when no segments have a width equal to or greater than a target width, theoretically combining the segment having the highest bit-loading value with its immediate neighbor segment having a next highest bit-loading value to create a combined segment having a combined width at the next highest bit-loading value, then choosing the combined segment when the combined width is equal to or greater than the target width;
- or
- (iii) repeating step (ii) until a combined segment with the target width is created.
Dependencies are inferred from the claim text.