Non orthogonal multiple access for DS-CDMA systems

2021 ◽  
Vol 36 (4) ◽  
pp. 222
Author(s):  
Raed Alhamad ◽  
Hatem Boujemaa
Keyword(s):  
Multiple Access ◽  
Cdma Systems

Study of Power Control in CDMA System on the basis of optimization Technique

2017 ◽  
Vol 7 (8) ◽  
pp. 126
Author(s):  
. Geetanjli
Keyword(s):  
Power Control ◽  
Multiple Access ◽  
Optimization Technique ◽  
System Optimization ◽  
Base Station ◽  
Particle Swarm Algorithm ◽  
Cdma System ◽  
Frequency Division ◽  
Cdma Systems ◽  
Time Division

The power control in CDMA systems, grant numerous users to share resources of the system uniformly between each other, leading to expand capacity. With convenient power control, capacity of CDMA system is immense in contrast of frequency division multiple access (FDMA) and time division multiple access (TDMA). If power control is not achieved numerous problems such as the near-far effect will start to monopolize and consequently will reduce the capacity of the CDMA system. However, when the power control in CDMA systems is implemented, it allows numerous users to share resources of the system uniformly between themselves, leading to increased capacity For power control in CDMA system optimization algorithms i.e. genetic algorithm & particle swarm algorithm can be used which regulate a convenient power vector. These power vector or power levels are dogged at the base station and announce to mobile units to alter their transmitting power in accordance to these levels. The performances of the algorithms are inspected through both analysis and computer simulations, and compared with well-known algorithms from the literature.

Robust MVDR Estimation via Polynomial Rooting for MC-CDMA Carrier Frequency Offset

2013 ◽  
Vol 284-287 ◽  
pp. 2687-2693
Author(s):  
Ing Jiunn Su ◽  
Chiao Chan Huang
Keyword(s):  
Carrier Frequency ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Carrier Frequency Offset ◽  
Low Complexity ◽  
Frequency Offset ◽  
High Accuracy ◽  
Cdma Systems ◽  
Code Division Multiple ◽  
Polynomial Rooting

In this letter, we present a blind carrier frequency offset (CFO) estimator by exploiting the polynomial rooting technique for multicarrier-code division multiple access (MC-CDMA) systems. Relative high accuracy and low-complexity to the CFO estimation can be achieved by rooting a polynomial. Simulation results are provided for illustrating the effectiveness of the proposed blind polynomial rooting estimator.

Lattice Reduction Algorithm Based Uplink MC-CDMA

2015 ◽  
Vol 738-739 ◽  
pp. 391-396
Author(s):  
Umut Yunus ◽  
Askar Hamdulla ◽  
Zhen Hong Jia ◽  
Kurban Ubul
Keyword(s):  
Communication Systems ◽  
Multiple Access ◽  
Multiple Input Multiple Output ◽  
Lattice Reduction ◽  
Rate Performance ◽  
Multiple Input ◽  
High Spectral Efficiency ◽  
Input Multiple Output ◽  
Cdma Systems ◽  
Multi Access

MC-CDMA integrates the advantages of OFDM with those of CDMA, it has high spectral efficiency, robustness against multi-path propagation and multiple access flexibility. Due to the above mentioned merits, it has been considered as a candidate for future wireless. In recent years, lattice reduction technique is discussed in multiple input multiple output communication systems, and has been shown with its better performance. The purpose of this paper is to express a model for uplink MC-CDMA systems in matrix form and then to propose a lattice reduction aided multiuser detection, in order to ameliorate the affects of inter-carrier interference and multi access interference. The effectiveness of the proposed method is evaluated by the bit error rate performance.

scholarly journals Frequency-Domain Oversampling for Cognitive CDMA Systems: Enabling Robust and Massive Multiple Access for Internet of Things

IEEE Access ◽  
2016 ◽  
Vol 4 ◽  
pp. 4583-4589 ◽  
Author(s):  
Su Hu ◽  
Huiting Guo ◽  
Chuanxue Jin ◽  
Yixuan Huang ◽  
Bin Yu ◽  
...  
Keyword(s):  
Internet Of Things ◽  
Frequency Domain ◽  
Multiple Access ◽  
Cdma Systems

scholarly journals The Channel Shortening comparison between OFDM & MC-CDMA System over an ADSL Channel using a Water-filling

2019 ◽  
Vol 9 (5) ◽  
pp. 3695
Author(s):  
Bouasria Fatima
Keyword(s):  
System Performance ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Digital Transmission ◽  
Cdma System ◽  
Channel Shortening ◽  
Multiple Paths ◽  
Water Filling ◽  
Cdma Systems ◽  
Code Division Multiple

<p>In this paper our objective focuses on the development of digital transmission techniques in order to solve the problem of Inter-Symbol Interference (ISI) due to multiple paths and the improvement of Multi-Carrier Code Division Multiple Access (MC-CDMA) system performance. The both algorithm: MERRY algorithm (Multicarrier Equalization by Restoration of Redundancy) called TEQ (Time domain EQualizer) and the power allocation method to allocate appropriate power to each user (Water-filling technique (WF)) [1] is used. Finally, the numerical results show that combining Water Filling with TEQ technique allows to reduce the ISI for MC-CDMA systems.</p>

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