### Semester Thesis

# MAC schemes for two-way relaying in IEEE 802.11 WLANs

Assuming two wireless nodes A and B communicating via a relay R, in the conventional relaying schemes the first timeslot A transmits to R, in the second timeslot R transmits to B; in timeslot 3, B transmits to R, then R sends the data to A. As a result four timeslots are required to transfer the data from A to B and vice versa and the achievable rate suffers from the use of four timeslots. Such schemes are used to increase the coverage or to reduce the overall transmit power. In two-way relaying [1] two wireless nodes A and B are communicating via a relay R as it is seen in the following figure. In the first timeslot, A and B transmitting to R and in the second timeslot, R retransmits the received signal to both A and B. Hence only two timeslots is used for delivering the data from A to B and vice versa and the spectral efficiency is improved.

So far no relaying functions are defined in the current IEEE 802.11 MAC (medium access control).
The main goal of this work is to study and propose MAC schemes for two-way relaying in a WLAN system based
on IEEE 802.11. The performance of the MAC schemes will be analyzed using NS2 simulator.

[1] B. Rankov, and A. Wittneben, Spectral Efficient Protocols for Half-duplex Fading Relay Channels, submitted to IEEE Journal on Selected Areas in Communications, Feb. 2006.

Subject area | Two-way Relaying, IEEE 802.11e WLAN, MAC |
---|---|

Type of work | 50% Theory, 50% Software (NS-2) |

Student | Georgios Sotiropoulos |

Supervisors | Dr. Azadeh Ettefagh, Dr. Marc Kuhn |

Professor | Prof. Dr. Armin Wittneben |