000			03130nas a2200385 a 4500
005			20260817161531.0
008			100419s2009 th uu|m rtt 0| a1eng d
035			_a.b12074780
099		9	_aAIT Thesis no.TC-09-11
100	0		_aHo Thi Nhu Ngoc
245	1	0	_aAdaptive subchannel and power allocation for multiuser OFDM systems using buffer state information
260			_aPathum Thani, Thailand : _bAsian Institute of Technology, _c2009
300			_a38 leaves : _bill.
490	1		_aThesis ; _vno. TC-09-11
500			_aSubmitted in partial fulfillment of the requirements for the degree of Master of Engineering in Telecommunications, School of Engineering and Technology
502			_aThesis (M.Eng.) - Asian Institute of Technology, 2009
520			_aMultiuser OFDM is considered as a modulation and multiple access method for next generation wireless systems. It is being widely deployed in broadband wireless networks due to its capability to overcome the channel impairments and support high data rates. Adaptive subchannel and power allocation in the downlink of multiuser OFDM systems is presented in this thesis. The problem of maximizing the overall throughput subject to the total transmit power constraint for each user is considered. Compared to existing algorithms, the proposed algorithms is unique in trying to directly incorporate the queue size or buffer state information into the allocation decisions. Our algorithm is divided into two steps, namely subchannel assignment and power allocation. The subchannel assignment is based on not only the channel conditions but also the buffer state information of each user. In this way, the limited transmission resources can be utilized efficiently. The power allocation step is formulated as a convex optimization problem and solved by standard algorithms in Matlab. Matlab is used to simulate the multiuser OFDM system. Simulation results shows that the proposed algorithm achieves better throughput and delay performances than existing algorithms. Finally, the performance improvement obtained from the use of buffer state information is quantified.
650		0	_aOrthogonal frequency division multiplexing
700	0		_aPoompat Saengudomlert, _eChairperson
700	1		_aErke, Tapio J., _eExamination Committee
700	1		_aRajatheva, R.M.A.P, _eExamination Committee
710	2		_aAIT Fellowship, _eScholarship donor
810	2		_aAsian Institute of Technology. _tThesis ; _vno. TC-09-11
856			_3Full-Text _uhttp://203.159.5.9/ait-thesis/detail.php?q=B04057
907			_a.b12074780 _bmnait _cu
902			_a240329
998			_b0 _c100419 _dm _ea _fu _g0
945			_lmnait
945			_lmnarc
942			_c22
942			_c40
909			_aBarcode : 30050120811327 _bCREATED : 2014-04-21 _cRECORD # : i12790825 _dLPATRON : 0 _eLCHKIN : - _f# RENEWALS : 0 _g# OVERDUE : 0 _hIUSE3 : 0 _iTOT CHKOUT : 0 _jTOT RENEW : 0
909			_aBarcode : 30050160043393 _bCREATED : 2016-03-17 _cRECORD # : i1289509x _dLPATRON : 0 _eLCHKIN : - _f# RENEWALS : 0 _g# OVERDUE : 0 _hIUSE3 : 0 _iTOT CHKOUT : 0 _jTOT RENEW : 0
999			_c1635 _d1635