Ibrahim Al-kebsi | Sanaa Community College (original) (raw)
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Papers by Ibrahim Al-kebsi
Journal of Applied Sciences, 2008
... OFDM is actually a combination of both modulation and multiplexing (Mishra, 2007). ... Î:::::... more ... OFDM is actually a combination of both modulation and multiplexing (Mishra, 2007). ... Î:::::E 1 л ii T "* i\ \ i 1(Г- ====í===== í rR4h=== + 1 p ■¡~ Ì 1 ■ ~~' i \ i ' Nomai OFDM with A-Qf :-*-MPC (4+16+64-QAM) M ! \ ! \ 10 " 1 i 1 ^i-=hSs-8 PARO (dB) 10 ...
This paper tries to study the impact of modulation adaptation and power control on PAPR clipping ... more This paper tries to study the impact of modulation adaptation and power control on PAPR clipping technique by combining all these techniques together to produce a new algorithm not only to reduce the PAPR, but to improve the performance of the SER and enhance the data rate of OFDM signals for 4G systems. This algorithm is called MPC (modulation adaptation, power control and clipping) and it presents a new issue which is the ability of using the high order modulation schemes such as 256-QAM at low SNR values without degrading the SER performance.
Cognitive radio users are secondary users armed with sensing capability to observe any available ... more Cognitive radio users are secondary users armed with sensing capability to observe any available spectrum holes which are temporarily and/or spatially unused by the primary users to use them for their own transmission. In this context, the demand for maximizing the secondary users' network capacity while maintaining high protection level to primary users is very crucial. This research work presents two operational modes for the cognitive users' network, namely, constant primary user protection (CPUP) and constant secondary user spectrum usability (CSUSU). The simulation results show that cooperating all secondary users in the network does not necessarily lead to attain the optimum performance, but instead, it is achieved by cooperating a certain number of users who possess the highest primary user's signal-to-noise ratio values at their receivers.
Abstract This paper tries to present a new form of adaptive modulation which has the ability of ... more Abstract This paper tries to present a new form of adaptive modulation which has the ability of using the high order modulation schemes such as 256-QAM and 128-QAM at low SNR values such as 2, 4 and 8 dB in order to enhance the data rate without degrading the SER ...
Journal of Applied Sciences, 2008
... OFDM is actually a combination of both modulation and multiplexing (Mishra, 2007). ... Î:::::... more ... OFDM is actually a combination of both modulation and multiplexing (Mishra, 2007). ... Î:::::E 1 л ii T "* i\ \ i 1(Г- ====í===== í rR4h=== + 1 p ■¡~ Ì 1 ■ ~~' i \ i ' Nomai OFDM with A-Qf :-*-MPC (4+16+64-QAM) M ! \ ! \ 10 " 1 i 1 ^i-=hSs-8 PARO (dB) 10 ...
This paper tries to study the impact of modulation adaptation and power control on PAPR clipping ... more This paper tries to study the impact of modulation adaptation and power control on PAPR clipping technique by combining all these techniques together to produce a new algorithm not only to reduce the PAPR, but to improve the performance of the SER and enhance the data rate of OFDM signals for 4G systems. This algorithm is called MPC (modulation adaptation, power control and clipping) and it presents a new issue which is the ability of using the high order modulation schemes such as 256-QAM at low SNR values without degrading the SER performance.
Cognitive radio users are secondary users armed with sensing capability to observe any available ... more Cognitive radio users are secondary users armed with sensing capability to observe any available spectrum holes which are temporarily and/or spatially unused by the primary users to use them for their own transmission. In this context, the demand for maximizing the secondary users' network capacity while maintaining high protection level to primary users is very crucial. This research work presents two operational modes for the cognitive users' network, namely, constant primary user protection (CPUP) and constant secondary user spectrum usability (CSUSU). The simulation results show that cooperating all secondary users in the network does not necessarily lead to attain the optimum performance, but instead, it is achieved by cooperating a certain number of users who possess the highest primary user's signal-to-noise ratio values at their receivers.
Abstract This paper tries to present a new form of adaptive modulation which has the ability of ... more Abstract This paper tries to present a new form of adaptive modulation which has the ability of using the high order modulation schemes such as 256-QAM and 128-QAM at low SNR values such as 2, 4 and 8 dB in order to enhance the data rate without degrading the SER ...