Subject Area

Computer Engineering


In-band full duplex (IBFD) for wireless communication is defined as the ability of a node to send and receive data simultaneously by using the same frequency band. IBFD has the potential to double the spectral efficiency of wireless networks. In addition, IBFD improves security by mystifying any eavesdropper with multiple transmitted signals in a single frequency. Also, IBFD reduces the end-to-end transmission delay and solves the hidden terminal and exposed terminal problems. However, IBFD suffers from self-interference. Canceling self-interference (SI) is the main challenge in enabling IBFD. Another challenge for IBFD is to manage access to the network. IEEE802.11 are considering IBFD for the IEEE802.11be. However, IBFD deployment requires an advanced medium access control (MAC) protocol design to accommodate the full duplex operation to different wireless technologies. In this research, we propose multiple MAC protocols to exploit the benefits of IBFD.

First, we propose FD-MUMAC, a multiuser MAC protocol for an IBFD access point (AP) that serves multiple half-duplex users. The proposed protocol includes a mechanism for collecting channel state and interference data for uplink and downlink beamforming. The protocol also allows for a trade-off in fairness or rate in one traffic direction (such as downlink) to determine user selection in the other (such as uplink). Second, we investigate user selection challenges for a full duplex AP. Hence, we propose a throughput-fairness tradeoff selection algorithm that allows the AP to maximize throughput while maintaining a reasonable level of fairness. Furthermore, we propose a throughput-fairness MAC (TFMAC) based on the 802.11 standards to accommodate the proposed selection algorithm's requirements while supporting legacy nodes. Third, we investigate reducing the overhead in the current IBFD MAC protocols. Consequently, we propose a hybrid medium access control (HyFDMAC) protocol for infrastructure-based wireless networks that integrate random and scheduled access. HyFDMAC is a multistage protocol based on the IEEE 802.11 DCF that allows a full duplex AP to collect channel and interference information for multiuser transmission and ensure fairness. Finally, we investigate the challenges of multi-band WLAN operation. As a result, we propose the MB-FDMAC protocol, which is a fully integrated multi-band MAC protocol for a full duplex AP that supports IBFD and multiuser transmission to multi-band enabled half-duplex stations. MB-FDMAC primarily uses the sub-6 GHz band for control-frame exchange and the 60 GHz band for data-frame exchange to maximize utilization of the frequency band with the highest instantaneous bandwidth because control frames are transmitted at the lowest rate across the entire bandwidth. We also propose a method of station selection that ensures fairness between uplink and downlink stations. Furthermore, we propose a method to improve the utilization of the mmWave band's high bandwidth by incorporating time duplexing into MB-FDMAC, which improves fairness and significantly reduces packet delay.

Degree Date

Spring 12-17-2022

Document Type


Degree Name



Electrical and Computer Engineering


Dinesh Rajan

Number of Pages




Creative Commons License

Creative Commons Attribution-Noncommercial 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License