Uplink interference control in a wiMAX communication system
View Patent ↗An apparatus and method to provide uplink interference control in a WiMAX communication system includes a step 302 of receiving a downlink channel quality indication from an MS. A next step 304 selecting a modulation product ratio modification parameter in response to the channel quality indication. A next step 306 includes modifying a modulation product ratio by the modification parameter. A next step 308 includes mapping the modified modulation product ratio against a table of modulation coding schemes. A next step 312 includes applying the mapped modulation coding scheme.
1. A method to provide uplink interference control in a communication system, the method comprising the steps of:
defining at least one modulation product ratio modification parameter;
receiving a downlink channel quality indication from a mobile station;
selecting an uplink modulation product ratio modification parameter in response to the downlink channel quality indication;
modifying an uplink modulation product ratio by the modulation product ratio modification parameter determined by the downlink channel quality indication;
mapping the uplink modified modulation product ratio against a table of modulation coding schemes;
limiting an uplink modulation coding scheme level to be equal or less than a downlink modulation coding scheme level; and
instructing the mobile station to apply the mapped uplink modulation coding scheme;
wherein the selecting step includes selecting an uplink modulation product ratio modification parameter MPR max i in response to the downlink channel quality indication:
MPR max i =A ·log 2 (1 +B·D info ·SINR i )
where MPR max i is the highest modulation product ratio for the i th mobile station that can allocated by the uplink scheduler, SINR i is Signal-to-Interference-plus-Noise Ratio for the i th mobile station, and A and B are scheduler parameters, and where the modification parameter D info is the modification parameter determined from the defining and selecting steps.
2. The method of claim 1 wherein the selecting step occurs dynamically upon the receiving step receiving a channel quality indication.
3. The method of claim 1 wherein the steps are performed once per frequency reuse scheme.
4. The method of claim 1 wherein the modifying step includes modifying the modulation product ratio as:
MPR i =min( MPR 0 i , MPR max i )
where MPR 0 i is the modulation product ratio determined by an uplink scheduler based on uplink interference and mobile transmit power and MPR max i is the uplink modulation product ratio modification parameter corresponding to highest modulation product ratio for the i th mobile station in response to its downlink channel quality indication.
5. A method to provide uplink interference control in a WiMAX communication system, the method comprising the steps of:
defining at least one modulation product ratio modification parameter;
receiving a downlink channel quality indication from a mobile station by a scheduler of a base station;
selecting an uplink modulation product ratio modification parameter in response to the downlink channel quality indication by the scheduler;
modifying an uplink modulation product ratio by the uplink modulation product ratio modification parameter determined by the downlink channel quality indication by the scheduler;
mapping the uplink modified modulation product ratio against a table of modulation coding schemes by the scheduler;
limiting an uplink modulation coding scheme level to be equal or less than a downlink modulation coding scheme level; and
instructing the mobile station to apply the mapped uplink modulation coding scheme as a maximum modulation coding scheme;
wherein the selecting step includes selecting an uplink modulation product ratio modification parameter MPR max i in response to the downlink channel quality indication:
MPR max i =A ·log 2 (1 +B·D info ·SINR i )
where MPR max i is the highest modulation product ratio for the i th mobile station that can allocated by the uplink scheduler, SINR i is Signal-to-Interference-plus-Noise Ratio for the i th mobile station, and A and B are scheduler parameters, and where the modification parameter D info is the modification parameter determined from the defining and selecting steps.
6. The method of claim 5 wherein the selecting step occurs dynamically upon the receiving step receiving a channel quality indication.
7. The method of claim 5 wherein the steps are performed once per frequency reuse scheme.
8. The method of claim 5 wherein the modifying step includes modifying the modulation product ratio as:
MPR i =min( MPR 0 i , MPR max i )
where MPR 0 i is the modulation product ratio determined by an uplink scheduler based on uplink interference and mobile transmit power and MPR max i is the uplink modulation product ratio modification parameter corresponding to highest modulation product ratio for the i th mobile station in response to its downlink channel quality indication.
9. A base station in a communication system providing uplink interference control, the base station comprising:
a memory for holding a defined modulation product ratio modification parameter;
a receiver receiving a downlink channel quality indication from a mobile station; and
a scheduler coupled to the memory and receiver and operable to: select an uplink modulation product ratio modification parameter in response to the downlink channel quality indication; modify an uplink modulation product ratio by the modulation product ratio modification parameter determined by the downlink channel quality indication; map the uplink modified modulation product ratio against a table of modulation coding schemes, and instruct the mobile station to apply the mapped uplink modulation coding scheme;
wherein the scheduler selects an uplink modulation product ratio modification parameter MPR max i in response to the downlink channel quality indication:
MPR max i =A ·log 2 (1 +B·D info ·SINR i )
where MPR max i is the highest modulation product ratio for the i th mobile station that can allocated by the uplink scheduler, SINR i is Signal-to-Interference-plus-Noise Ratio for the i th mobile station, and A and B are scheduler parameters, and where the modification parameter D info is the modification parameter determined from the defining and selecting steps.
10. The base station of claim 9 wherein the scheduler selects the modification parameter dynamically upon receiving a channel quality indication.
11. The base station of claim 9 wherein the scheduler selects the modification parameter once per frequency reuse scheme.
12. The base station of claim 9 wherein the scheduler modifies the modulation product ratio as:
MPR i =min( MPR 0 i , MPR max i )
where MPR 0 i is the modulation product ratio determined by an uplink scheduler based on uplink interference and mobile transmit power and MPR max i is the uplink modulation product ratio modification parameter corresponding to highest modulation product ratio for the i th mobile station in response to its downlink channel quality indication.