The IEEE 802.11bn draft amendment to the 802.11 Wi-Fi standard introduces Non-Primary Channel Access (NPCA) to enhance spectrum efficiency and mitigate congestion in dense wireless environments. NPCA allows stations to transmit over non-primary channels when the primary channel is occupied, improving overall spectrum utilization and reducing transmission delays. This paper presents a detailed evaluation of NPCA, focusing on its effectiveness in scenarios involving hidden nodes—one of the key challenges limiting its performance. Our research models NPCA based on IEEE contributions and proposals, implementing realistic network topologies to analyze both its strengths and weaknesses. The findings provide critical insights into NPCA’s practical deployment, highlighting its potential benefits and identifying areas requiring further optimization to ensure fairness and adaptability in real-world networks.

The increasing demand for high-performance wireless communication, due to emerging applications such as augmented reality, virtual reality, and Internet-of-Things (IoT), has highlighted the need for enhanced Peer-to-Peer (P2P) communication in Wi-Fi networks. P2P communication, often implemented through technologies like Wi-Fi Direct and Wi-Fi Aware, plays a crucial role in enabling seamless device-to-device interaction. This paper explores two significant enhancements for improving P2P communication: enhancing base-channel P2P through the optimization of TXOP sharing for P2P groups, and improving off-channel P2P through multi-AP coordination for channel advertisement. First, we examine the enhancement of base-channel P2P communication by introducing a refined transmission opportunity (TXOP) sharing mechanism, where an AP allocates portions of its TXOP to P2P devices within a group. This allocation ensures that devices can transmit data within a controlled, synchronized framework, thereby reducing contention and improving overall throughput. Furthermore, the proposed improvements enable devices to efficiently share resources based on group-level needs, supporting latency-sensitive applications such as real-time media streaming. Second, we address the challenges of off-channel P2P communication in OBSS (Overlapping Basic Service Set) environments, where interference from neighboring networks can severely affect performance. Through multi-AP coordination, APs can advertise recommended P2P channels that minimize overlap with infrastructure operations, thereby providing cleaner and more reliable channels for P2P communication. In addition, this coordination also facilitates faster setup and more efficient operation of P2P links.

To address 5G challenges, IEEE 802.11 is currently developing new amendments to the Wi-Fi standard, the most promising of which is 802.11ax. A key scenario considered by the developers of this amendment is dense and overlapped networks typically present in residential buildings, offices, airports, stadiums, and other places of a modern city. Being crucial for Wi-Fi hotspots, the hidden station problem becomes even more challenging for dense and overlapped networks, where even access points (APs) can be hidden. In this case, user stations can experience continuous collisions of beacons sent by different APs, which can cause disassociation and break Internet access. In this paper, we show that beacon collisions are rather typical for residential networks and may lead to unexpected and irreproducible malfunction. We investigate how often beacon collisions occur, and describe a number of mechanisms which can be used to avoid beacon collisions in dense deployment. Specifically, we pay much attention to those mechanisms which are currently under consideration of the IEEE 802.11ax group.

Very high-speed digital subscriber line (VDSL) upstream data transmission in a distributed environment will suffer from relatively strong far-end crosstalk generated by the shorter lines in the binder. This effect can dramatically reduce the upstream capacity on longer lines. To secure the capacity on lines of all lengths, shorter lines will be required to systematically reduce their transmit power. This power reduction is known as (upstream) power backoff (PBO or UPBO). This paper reviews the problem and summarizes a number of PBO techniques and results that may not be readily available in the published literature. Next, a general formulation is presented in terms of a "reference PSD" and a method is proposed to determine the optimal value of the reference PSD. This paper is mainly based on work that was done in VDSL standardization. It is an extended version of work that was previously published.

VDSL upstream data transmission in a distributed environment will suffer from relatively strong FEXT (far-end crosstalk) generated by the shortest lines in the topology. This can drastically reduce the upstream capacity on longer lines. To remedy this problem, a systematic reduction of the transmit power on shorter lines has to be applied. This principle is known as power back-off. This paper shows how power back-off can be formulated and how an optimal solution can be found.