Evaluating OFDMA and TWT in Wi-Fi 6/7 for QoS Assurance in IoMT Networks

Many existing healthcare facilities still rely on the aging Wi-Fi 5 (IEEE 802.11ac) standard, which is based on Orthogonal Frequency-Division Multiplexing (OFDM). OFDM supports single-user-per-channel access, leading to increased contention, higher latency, jitter, and packet loss under dense device deployments commonly found in clinical settings. This study presents a quantitative performance evaluation of Wi-Fi 5 and Wi-Fi 6/7 by comparing the effectiveness of OFDM with Orthogonal Frequency-Division Multiple Access (OFDMA) and Target Wake Time (TWT) in a simulated dense IoMT environment. Simulations were conducted using Network Simulator 3 (NS-3), and key Quality of Service (QoS) metrics. The results demonstrate that OFDMA reduces average network delay by up to approximately 30%, improves throughput by approximately 20%, and reduces packet loss ratio by up to 85% compared to OFDM under high-density conditions, while exhibiting marginally improved jitter performance (approximately 2%). In addition, the use of TWT achieved substantial reductions in device power consumption of up to approximately 90%, at the cost of reduced aggregate throughput of up to approximately 75% under high station densities. These results demonstrate that Wi-Fi 6/7 technologies offer significant advantages in terms of QoS and energy efficiency over legacy Wi-Fi 5 for dense IoMT environments.