SEGMENT SENSITIVE SCHEDULING

• US 20090201872A1
• Filed: 02/18/2009
• Published: 08/13/2009
• Est. Priority Date: 08/22/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Ji, Tingfang, Gorokhov, Alexei Y.
• Granted Patent: US 9,240,877 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 25/0398 Restoration of channel reciprocity
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0057 Physical resource allocation for CQI
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04L 5/1438 Negotiation of transmission parameters prior to communication modified according to link quality H04L1/0001

Abstract

Systems and methods of scheduling sub-carriers in an OFDMA system in which a scheduler takes into account channel conditions experienced by the communication devices to optimize channel conditions. The scheduler can partition a set of sub-carriers spanning an operating bandwidth into a plurality of segments. The segments can include a plurality of global segments that each includes a distinct non-contiguous subset of the sub-carriers spanning substantially the entire operating bandwidth. One or more of the global segments can be further partitioned into a plurality of local segments that each has a bandwidth that is less than a channel coherence bandwidth. The scheduler determines channel characteristics experienced by each communication device via reporting or channel estimation, and allocates one or more segments to communication links for each device according to the channel characteristics.

Claims

1. An apparatus for c scheduling in a communication system including a plurality of sub-carriers spanning an operating frequency band, the apparatus comprising:

a channel estimator configured to determine a channel estimate corresponding to each of a plurality of segments spanning the operating frequency band based on the pilot signal, each of the segments having a bandwidth less than a total bandwidth;

a signal mapper configured to map data symbols to a subset of the plurality of sub-carriers in the communication system; and

a scheduler coupled to the channel estimator and configured to determine

a first preferred segment based on the channel estimates, select the subset of the plurality of sub-carriers from within the first preferred segment, and further configured to control the signal mapper to map the data symbols to the subset of the plurality of sub carriers.

2. The apparatus of claim 1, further comprising a receiver module configured to receive reverse link pilot signals and wherein the scheduler is configured to select the subset of the plurality of sub-carriers for a forward link transmission based on the reverse link pilot signals.

3. The apparatus of claim 1, wherein the pilot signals comprise reverse link pilot signals and the scheduler is configured to generate a reverse link resource assignment message for transmission to a user terminal based on the channel estimates.

4. The apparatus of claim 1, wherein the scheduler is configured to select the first preferred segment as a segment having a largest signal to noise ratio determined from the pilot signals.

5. The apparatus of claim 1, further comprising:

a Channel Quality Indicator (CQI) receiver coupled to the receiver module and configured to process channel characteristic reporting messages received by the receiver to determine a second preferred segment and further configured to generate a resource assignment message based on the channel characteristic reporting messages.

6. The apparatus of claim 1, further comprising a frequency hopper module configured to enforce a frequency hopping scheme within the first preferred segment.