Performance of Cooperative ofdm

Topics: Radio resource management, Diversity scheme, Orthogonal frequency-division multiplexing Pages: 5 (2489 words) Published: April 16, 2014
Performance Analysis of OFDM Systems using Cooperative Diversity Techniques Abstrac t: Cooperative Diversity has been widely used in wireless network, and Orthogonal frequency division multiplexing (OFDM) is a key technique of multi-carrier transmission to meet high data rate requirement of wireless communication. The aim of this project is to combine the technology of OFDM with cooperative diversity techniques. The simulation will be done in MATLAB. The performance of the system will be compared by employing various techniques at the cooperative node. As of now, an application program has been designed about Cooperative Diversity in the OFDM system by combining the technology of orthogonal frequency division multiplexing (OFDM) with cooperative diversity techniques. Simulation results should show ,which system achieves a better error rate performance and at the same time obtain a significant diversity gain on the commonly used multi-path fading channel. In this project Amplify and Forward ,Decode and Forward and Coded Cooperation diversity techniques will be explored , to obtain better performance for OFDM systems. I. Introduction:

Multiple antennas transmitting diversity techniques have been investigated based on their ability to combat fading induced by multi-path of the channel, and have been widely used in wireless communication system. However, the deployment of antenna array on mobile terminal is difficult due to the size and power limitation. In order to solve this problem, a new mode of gaining transmit diversity called Cooperative Diversity has been proposed and widely studied. The idea of Cooperative Diversity is: in multi-user communication environment, some single-antenna users sharing other users’ antennas form a virtual antenna array to transmit each other's data to the receiver based on some protocol. Orthogonal Frequency Division Multiplexing (OFDM), as one of the most promising technology of future broadband wireless communication systems, has attracted much interest due to its high data rate, high spectrum efficiency, and robustness to frequency-selective channels. Orthogonal Frequency-Division Multiplexing (OFDM) is a high spectral efficiency type of multi-carrier modulation systems, which have many advantages over single-carrier systems, especially for high data-rates transmission in time dispersive channels . The main implications of this project shall be that the diversity gains from both spatial domain and frequency domain shall be combined and so cooperative communication should be able to further enhance the reliable, high speed transmission,and enable the spectrum efficiency. Cooperative OFDM scheme should be able to guarantee full cooperative diversity. II. Cooperative Diversity:

Cooperative Diversity is a transmission technique where introduction of relay channels generates independent paths between user and base station. Relay channel basically acts as an auxillary to the direct communication between source and destination[1].The type of processing of transmitted signal employed at the relay is a major aspect of various cooperative communication schemes. The destination can listen to both source and relay. However in most of the cases the destination only processes the signal from the relay. The main reason behind this could be that, since the source is generally further away from the destination than the relay, the relay signal shall be much stronger than he source signal. A significant amount of loss is seen in this case compared to the scenario where both signals from relay and destination are considered . The main advantage of relaying is that it provides diversity and prevents path loss [2].Cooperative communication protocols are broadly classified into fixed and adaptive relaying schemes. In fixed relaying, the channel resources are divided between the source and the relay in a fixed (deterministic) manner. The processing at the relay differs...

References: 1. Cooperative Communications and Networking: K.J.Ray Liu, Ahmed K Sadek, Weifung Su, Andre Kwasinski
2.Coded Cooperative Communications :Kamal Khatir
3. Diversity through Coded Cooperation Todd E. Hunter, Member, IEEE and Aria Nosratinia, Senior Member, IEEE
4. OFDM for Wireless Communications Systems by Ramjee Prasad
5. OFDM Communications with Cooperative Relays H. Lu1, H. Nikookar1 and T. Xu2 1.International Research Centre for Telecommunications and Radar (IRCTR) 2.Circuits and Systems Group (CAS) Dept.EEMCS, Delft University of Technology Mekelweg 4, 2628 CD, Delft, The Netherlands
Continue Reading

Please join StudyMode to read the full document

You May Also Find These Documents Helpful

  • Ofdm Essay
  • Ofdm Essay
  • Cooperatives Essay
  • Report on Ofdm Essay
  • Performance of Turbo Coded Ofdm in Wireless Local Area Network (Wlan) Research Paper
  • Essay about performance measurement
  • Essay about performance review
  • Essay on Performance

Become a StudyMode Member

Sign Up - It's Free