US 2018/0027507 A1 · METHOD AND APPARATUS FOR POWER AND USER DISTRIBUTION TO SUB-BANDS IN NOMA SYSTEMS

Abstract

Power allocation in NOMA systems for example on the basis Proportional Fairness calculations depends on knowledge of user throughput on a specified sub-band, which implies that users have already been allocated to particular sub-bands. Meanwhile, maximum throughput can generally be achieved where there is the greatest possible difference in transmission power for the users on a given sub-band, so that optimal allocation of users to sub-bands requires knowledge of the power available for each user. A mechanism is proposed based on iteratively applying a waterfilling algorithm to distribute power across a progressive subset of sub-bands to provisionally distribute the power budget across that subset of sub-bands, where at each iteration the water filling algorithm is carried out for each possible combination of users assignable to the newly considered sub-band using a floor for that sub band proportional to the reciprocal of the square of the highest channel gain value of any user in that combination, and calculating a throughput for that combination with the corresponding power attribution, whereby the combination retained for the next iteration (with an additional sub-band) is whichever gives the highest throughput. This process is thus repeated until users are assigned to all sub-bands, whereupon power allocations from the last iteration are definitive.

Claims10

Dependent claims

A device for distributing a transmission power budget amongst a plurality of sub-bands in a transmission system, said device being adapted to:

select one said sub-band for consideration,
determine every possible combination of users assignable to said sub-band under consideration;
assess each said possible combination of users assignable to the sub-band under consideration
to select the channel gain value of the user in that combination having the highest channel gain,
to determine a sub-band attenuation value proportional to the reciprocal of the square of said selected channel gain value;
to apply a water filling algorithm across said selected sub-band and every sub-band selected previously using a floor for each said sub-band defined by the respective said sub-band attenuation value,
to calculate a provisional power allocation from said water filling algorithm for said selected sub-band, and
to calculate a performance metric with said provisional power attribution;
and to attribute to said selected sub-band whichever said combination of users optimises said performance metric;
said device being further adapted to then select a further said sub-band and to repeat said operations of:
assess each said possible combination of users assignable to said sub-band under consideration;
and
attributing to said sub-band whichever said combination of users optimises said performance metric;
until all said sub-bands have been considered, and to
calculate a final power allocation for each said sub-band from the last iteration of the water filling algorithm corresponding to the combination of users selected for each said sub-band.

12 more elements

A method of distributing a transmission power budget amongst a plurality of sub-bands in a transmission system, said method comprising the steps of:

selecting one said sub-band for consideration;
determining every possible combination of users assignable to said sub-band under consideration;
assessing each said possible combination of users assignable to the sub-band under consideration
to select the channel gain value of the user in that combination having the highest channel gain,
to determine a sub-band attenuation value proportional to the reciprocal of the square of said selected channel gain value,
to apply a water filling algorithm across said selected sub-band and every sub-band selected previously using a floor for each said sub-band defined by the respective said sub-band attenuation value,
to calculate a provisional power allocation from said water filling algorithm for said selected sub-band, and
to calculate a performance metric with said provisional power attribution;
and attributing to said selected sub-band whichever said combination of users optimises said performance metric;
said method comprising the further steps of selecting a further said sub-band and repeating said steps of
assessing for each said possible combination of users;
and
attributing to said sub-band whichever said combination of users optimises said performance metric;
until all said sub-bands have been considered, and
calculating a final power allocation for each said sub-band from the last iteration of the water filling algorithm corresponding to the combination of users selected for each said sub-band.

12 more elements

Dependencies are inferred from the claim text.

Method and apparatus for power and user distribution to sub-bands in noma systems

Life of this patent

Method and apparatus for power and user distribution to sub-bands in noma systems

Life of this patent

Abstract

Claims10