Peak-to-average power ratio control
View Patent ↗A method for reducing the peak-to-average power ratio (PAPR) in an OFDM based wireless system is disclosed herein. The reduced PAPR may be achieved by appropriately selecting subpackets for transmission. For example, a scheduler may elect to sequentially transmit the subpackets in an order related to the PAPR of each of the subpackets until at least one of the subpackets is properly received. In one embodiment of the instant invention the order of transmission is selected to be from lowest to highest PAPR.
1. A method of transmitting information included in an encoded packet, the method comprising:
forming, at a base station, a first and second subpacket from the encoded packet such that decoding at least one of the first and second subpackets recovers the information included in the encoded packet;
determining, at the base station, a peak-to-average power ratio for each of the first and second subpackets; and
transmitting, from the base station, at least one of the first and second subpackets using a hybrid automatic repeat request protocol, wherein the first or second subpacket is selected for transmission in an order related to the peak-to-average power ratio of each subpacket, wherein transmitting at least one of the first and second subpackets in an order related to the peak-to-average power ratio of each subpacket further comprises transmitting the subpacket having the lowest peak-to-average power ratio first, and transmitting the subpacket having a higher peak-to-average ratio second in response to receiving a signal that the subpacket having the lowest peak-to-average power ratio was not received properly;
forming, at the base station, a third and fourth subpacket from a subsequent set of information in response to receiving a signal indicating that at least one of the first and second subpackets was received properly;
determining, at the base station, a peak-to-average power ratio for each of the third and fourth subpackets; and
transmitting, from the base station, at least one of the third and fourth subpackets in an order related to the peak-to-average power ratio of each subpacket.
2. A method of transmitting information included in an encoded packet, the method comprising:
forming, at a base station, a first and second subpacket from the encoded packet such that decoding at least one of the first and second subpackets recovers the information included in the encoded packet;
determining, at the base station, a peak-to-average power ratio for each of the first and second subpackets; and
transmitting, from the base station, at least one of the first and second subpackets using a hybrid automatic repeat request protocol, wherein the first or second subpacket is selected for transmission in an order related to the peak-to-average power ratio of each subpacket.
3. A method, as set forth in claim 2 , wherein transmitting at least one of the first and second subpackets in an order related to the peak-to-average power ratio of each subpacket further comprises transmitting the subpacket having the lowest peak-to-average power ratio first.
4. A method, as set forth in claim 2 , wherein transmitting at least one of the first and second subpackets in an order related to the peak-to-average power ratio of each subpacket further comprises transmitting the subpacket having the lowest peak-to-average power ratio first, and transmitting the subpacket having a higher peak-to-average ratio second in response to receiving a signal that the subpacket having the lowest peak-to-average power ratio was not received properly.
5. A method, as set forth in claim 2 , wherein forming a first and second subpacket from the information further comprises forming a first and second self-decodable subpacket from the information, wherein decoding either the first or second self-decodable subpacket recovers the information included in the encoded packet.
6. A method of transmitting information included in an encoded packet, the method comprising:
forming, at a base station, a plurality of subpackets from the encoded packet such that decoding at least one of the subpackets recovers the information included in the encoded packet;
determining, at the base station, a peak-to-average power ratio for at least a portion of the plurality of subpackets; and
transmitting, from the base station, the plurality of subpackets according to a hybrid automatic repeat request protocol, wherein the plurality of subpackets are transmitted in an order related to the peak-to-average power ratio of each subpacket.
7. A method, as set forth in claim 6 , wherein transmitting at least one of the plurality of subpackets in an order related to the peak-to-average power ratio of each subpacket further comprises transmitting the subpacket having the lowest peak-to-average power ratio first.
8. A method, as set forth in claim 6 , wherein transmitting at least one of the plurality of subpackets in an order related to the peak-to-average power ratio of each subpacket further comprises transmitting the subpacket having the lowest peak-to-average power ratio first, and transmitting the subpacket having the next lowest peak-to-average ratio thereafter in response to receiving a signal that the subpacket having the lowest peak-to-average power ratio was not received properly.
9. A method, as set forth in claim 6 , wherein transmitting at least one of the plurality of subpackets in an order related to the peak-to-average power ratio of each subpacket further comprises sequentially transmitting each of the subpackets in an order of lowest to highest peak-to-average power ratio until receiving a signal that at least one of the subpackets was properly received.
10. A method, as set forth in claim 6 , wherein transmitting at least one of the plurality of subpackets in an order related to the peak-to-average power ratio of each subpacket further comprises:
selecting a first subpacket; and
transmitting the first subpacket in response to the peak-to-average power ratio of the selected subpacket being less than a preselected setpoint.
11. A method, as set forth in claim 10 , further comprising:
selecting a second subpacket in response to receiving a signal that the first subpacket was not properly received; and
transmitting the second subpacket in response to the peak-to-average power ratio of the selected subpacket being less than a preselected setpoint.
12. The method of claim 6 , wherein, forming the plurality of subpackets comprises forming a plurality of self-decodable packets such that decoding any one of the self-decodable subpackets or any combination of the self-decodable subpackets recovers the information included in the encoded packet.
13. A method of receiving information included in an encoded packet, the method comprising:
receiving, at a mobile unit, at least one of a first and second subpacket transmitted by a base station according to a hybrid automatic repeat request protocol, the first and second subpackets being received in an order related to a determined peak-to-average power ratio for each of the subpackets, each subpacket being formed from the encoded packet such that decoding at least one of the first and second subpackets recovers the information included in the encoded packet.
14. A method of transmitting information included in an encoded packet, the method comprising:
transmitting, from a base station, at least one of a first and second subpacket according to a hybrid automatic repeat request protocol, wherein the first and second subpacket are transmitted in an order related to a determined peak-to-average power ratio for each of the subpackets, each subpacket being formed from the encoded packet such that decoding at least one of the first and second subpackets recovers the information included in the encoded packet.