Outer-loop scheduling design for communication systems with channel quality feedback mechanisms
First Claim
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1. In a wireless communication system, an apparatus for transmitting a packet in a transmission format, comprising:
- a receiving subsystem for receiving channel quality information from a remote station;
a scheduling element for inserting a data payload into a packet for transmission, wherein the scheduling element is configured to use a outer-loop algorithm to determine the feasibility of a transmission format for the packet and to alter the parameters of the outer-loop algorithm in accordance with the channel quality information, and wherein the scheduling element is further configured to determine the parameters from a channel variation rate derived from a fading curve reconstructed from the channel quality information; and
a transmission subsystem for transmitting the packet to the remote station.
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Abstract
Methods and apparatus are presented for dynamically adjusting parameters of an outer-loop algorithm, which is used to determine the feasibility of a transmission format. The parameters of the outer-loop algorithm are adjusted according to channel conditions. In one embodiment, an erasure-based approach is used to determine whether to incrementally increase or incrementally decrease a margin parameter in the outer-loop algorithm. Once one margin parameter is altered, other margin parameters can be adjusted accordingly.
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Citations
25 Claims
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1. In a wireless communication system, an apparatus for transmitting a packet in a transmission format, comprising:
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a receiving subsystem for receiving channel quality information from a remote station; a scheduling element for inserting a data payload into a packet for transmission, wherein the scheduling element is configured to use a outer-loop algorithm to determine the feasibility of a transmission format for the packet and to alter the parameters of the outer-loop algorithm in accordance with the channel quality information, and wherein the scheduling element is further configured to determine the parameters from a channel variation rate derived from a fading curve reconstructed from the channel quality information; and a transmission subsystem for transmitting the packet to the remote station. - View Dependent Claims (2, 3, 4)
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5. In a wireless communication system, an apparatus for transmitting a packet in a transmission format, comprising:
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a receiving subsystem for receiving channel quality information from a remote station, wherein the channel quality information is Carrier-to-Interference (C/I) values; a scheduling element for inserting a data payload into a packet for transmission, wherein the scheduling element is configured to use a outer-loop algorithm to determine the feasibility of a transmission format for the packet and to alter the parameters of the outer-loop algorithm in accordance with the channel quality information, wherein the scheduling element is further configured to reconstruct a fading curve using the C/I values, and wherein the scheduling element is further configured to determine a channel variation rate (CVR) using the fading curve; and a transmission subsystem for transmitting the packet to the remote station. - View Dependent Claims (6)
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7. In a wireless communication system, a method for adapting a margin parameter of an outer-loop algorithm used to schedule packet transmissions, comprising:
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receiving channel quality information from a remote station; determining a channel variation rate from the channel quality information; determining whether to increase or decrease the margin parameter by a margin increment, wherein the margin increment is based on the channel variation rate and the channel variation rate derived from a fading curve reconstructed from the channel quality information; comparing the margin parameter to a second margin parameter; and altering the second margin parameter according to a set of selection rules. - View Dependent Claims (8, 9)
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10. In a wireless communication system, a method for adapting a margin parameter of an outer-loop algorithm used to schedule packet transmissions, comprising:
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receiving channel quality information from a remote station; determining a channel variation rate from the channel quality information, wherein the channel quality information is carrier-to-interference (C/I) values; determining whether to increase or decrease the margin parameter by a margin increment, including; receiving a type of acknowledgment message from the remote station; if the type of acknowledgment message is an acknowledgment, then decreasing the margin parameter by the margin increment; and if the type of acknowledgment message is a negative acknowledgment, then increasing the margin parameter by the margin increment; comparing the margin parameter to a second margin parameter; and altering the second margin parameter according to a set of selection rules. - View Dependent Claims (11, 12, 13)
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14. An apparatus for formatting a packet into a transmission format, comprising:
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a memory element; and a processing element configured to execute a set of instructions on the memory element, the set of instructions for; determining fading curve representative of a transmission channel on which the packet is to be sent to a remote station; determining a margin offset to the fading curve based on a feedback message from the remote station, the feedback message including one of a channel variation rate determined by the remote station or Carrier-to-Interference (C/I) values; and determining whether a transmission format incorporating the margin offset is feasible for formatting the packet. - View Dependent Claims (15, 16, 17)
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18. An apparatus for formatting a packet into a transmission format, comprising:
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a memory element; and a processing element configured to execute a set of instructions on the memory element, the set of instructions for; determining a fading curve representative of a transmission channel on which the packet is to be sent to a remote station; determining a margin offset to the fading curve based on a feedback message from the remote station; determining whether a transmission format incorporating the margin offset is feasible for formatting the packet; determining a power requirement for the transmission format incorporating the margin offset; and determining the margin offset to the fading curve based on a velocity of the remote station, wherein the velocity is determined using Doppler estimation.
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19. An apparatus for formatting a packet into a transmission format, comprising:
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a memory element; and a processing element configured to execute a set of instructions on the memory element, the set of instructions for; determining a fading curve representative of a transmission channel on which the packet is to be sent to a remote station; determining a margin offset to the fading curve based on a feedback message from the remote station; determining the margin offset based on whether the margin offset is to be increased or decreased, and determining a decreasing margin offset according to;
Stepdecrease =Stepincrease/[1/(packet error rate)−
1],wherein Stepincrease is the increasing margin offset and “
packet error rate”
is a system parameter; anddetermining whether a transmission format incorporating the margin offset is feasible for formatting the packet.
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20. A method for formatting a packet into a transmission format, comprising:
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determining a fading curve representative of a transmission channel on which the packet is to be sent to a remote station; determining a margin offset to the fading curve based on a feedback message from the remote station, the feedback message including one of a channel variation rate determined by the remote station or Carrier-to-Interference (C/I) values; and determining whether a transmission format incorporating the margin offset is feasible for formatting the packet; and if feasible, then formatting the packet according the transmission format incorporating the margin offset. - View Dependent Claims (21, 22, 23)
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24. A method for formatting a packet into a transmission format, comprising:
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determining a fading curve representative of a transmission channel on which the packet is to be sent to a remote station; determining a margin offset to the fading curve based on a feedback message from the remote station and based on a velocity of the remote station; determining the margin offset based on whether the margin offset is to be increased or decreased, and determining a decreasing margin offset according to;
Stepdecrease =Stepincrease/[1/(packet error rate)−
1],wherein Stepincrease is the increasing margin offset and “
packet error rate”
is a system parameter;determining whether a transmission format incorporating the margin offset is feasible for formatting the packet; and if feasible, then formatting the packet according the transmission format incorporating the margin offset. - View Dependent Claims (25)
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Specification