radio resource allocation in ofdma system
abstract
in this thesis, orthogonal frequency division multiple access (ofdma) system is considered.
assuming perfect knowledge of instantaneous channel conditions for all users, we propose resource
allocation algorithms to minimize the total transmission power subject to the constraints
of the requirements of each user’s data rate and bit error rate (ber) which is referred to as
margin adaptive (ma) problem, or to maximize the overall spectral efficiency while simultaneously
satisfying the requirements of each user’s d ata rate, ber and base station (bs)’s
transmission power constraint which is referred to as rate adaptive (ra) problem. by converting
the above problems into linear integer programming problems, a branch-and-bound method
based optimal algorithm and a fast suboptimal algorithm are proposed. the proposed branch-and-
bound method based optimal algorithm offers the same optimal performance as full-search
algorithm with remarkably reduced computational complexity. the proposed suboptimal algorithm
, which is based on the formulation with constraints considered and greedy approach, can
be used to solve both ma and ra optimization problems by satisfying the constraints one by
one without any bit loading or transmission power distribution assumptions. compared with
other suboptimal methods, the performance of this suboptimal algorithm is close to the optimal
one with even lower computational complexity.
index terms-adaptive modulation, frequency selective fading channel, multi-access communication,
multiuser channel, channel capacity, orthogonal frequency division multiple access
(ofdma), power control, resource management.
collections
- retrospective theses [1604]