UniversitÉ Libanaise

UniversitÉ Saint-Esprit De Kaslik

Institut Mines-telecom

Institut Mines-telecom / Telecom Bretagne

Joumana Farah

Charbel Abdel Nour

Catherine Douillard

Marie-Rita Hojeij

A method and system for assigning power to sub-bands in a multiple access communications system, where users are assigned iteratively to sub-bands, and at each iteration a provisional partial power budget is determined for the subset of sub-bands comprising the sub-bands to which users have been assigned in the present time slot and the sub-band under consideration in the sequence, where the fraction of the total available power determined as the provisional partial power budget corresponds to the fraction of the number of sub-bands in the subset from the total number of sub-bands to be assigned, and the provisional power allocation for the sub-band under consideration is obtained by performing a waterfilling distribution of the provisional partial power budget amongst the subset of the sub-bands, based on the channel gain of the users already assigned to sub-bands in the present time slot.

Method and apparatus for power distribution to sub-bands in multiple access communications systems

A mechanism is presented for attributing users to one or more of a plurality of sub-bands in a multiple access communications system, wherein in an initial assignment phase, a first user is selected for a sub band, for example on the basis of a user priority. Users having complementary channel gains to that of the first user are identified, and then a second sub-band user maximizing a performance metric reflecting the achieved throughput, and/or fairness across users, is selected to accompany the first user on that sub-band. The initial assignment phase may terminate once all users have been assigned to a sub-band once. After the first phase is complete, the first user for each sub-band may be the user whose achieved total throughput is furthest from a target throughput defined for that user, wherein each user is assigned to the remaining sub-band to which no first user is currently attributed offering the highest channel gain for that user. Mechanisms for determining user priority, making provisional and definitive power allocations, and performance metrics are proposed.

Method and apparatus for user distribution to sub-bands in multiple access communications systems

A system and method for assigning users to a particular sub band in a given time slot in a NOMA system, where whichever pair of users corresponds to the smallest 'candidate pair user throughput deviation value', reflecting the aggregate of the respective difference between the average throughput across all users (K) and the known throughput of each of the two users under consideration (kk), and each user attributed to a sub-band other than the selected sub-band. User pairs for consideration may consider all possible pairs, or may be limited to candidate pairs satisfying together, or comprising one or both users who satisfy a criterion such as channel gain, distance to a target, throughput or a combination of some or all of these factors. The power allocated to each sub-band may be attributed by a waterfilling algorithm.

A method of determining a performance metric for a selection of a first user and a second user among a set of candidate users for attribution to a sub-band in a multiple access communications system based on Non-Orthogonal Multiple Access (NOMA), is provided wherein the first user (k) and the second user (k) are selected as the pair of candidate users corresponding to an extremum of the ratio between a first term reflecting the total throughput achievable by any pair of the candidate users assigned to the sub-band (s) under consideration, and a second term reflecting the known throughput achieved by that same pair of candidate users over a predetermined preceding period. Implementations include a method of determining a performance metric is presented for attributing users to one or more of a plurality of sub-bands in a multiple access communications system, wherein in an initial assignment phase for a specific sub-band, a first user is selected for that band on the basis of one or more criteria such as user priority. Then a second sub-band user maximizing or minimizing the performance metric.

User distribution to sub-bands in multiple access communications systems

A mechanism for attributing users to a plurality of sub bands in a time slot t in a multiple access communications system, said method comprising assigning a combination of users to a sub band on a Proportional Fairness basis, that is to say whichever combination of users maximizes a Proportional Fairness performance metric for that channel, where the performance metric is weighted by a weighting factor reflecting the difference for that user between a target throughput and a projected throughput.

Method and apparatus for user distribution to sub bands in NOMA systems

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.

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Mont Liban, Lebanon

Joumana Farah