# A Jamming-Resilient and Scalable Broadcasting Algorithm for Multiple Access Channel Networks
## 1 Introduction  
Ethernet and wireless local area networks (WLANs) have become the main building blocks of TCP/IP networks. These networks use multiple access channel (MAC) protocols to enable multiple nodes to communicate fairly and robustly through a shared channel. Ethernet networks use carrier sense multiple access/collision detection (CSMA/CD) in which the sender stops the transmission of the packet when a collision is detected. In addition, WLANs use carrier sense multiple access/collision avoidance (CSMA/CA), where the nodes attempt to avoid collision by waiting for an inter-frame spacing (IFS) time before transmitting a packet. These MAC protocols rely on an algorithm called binary exponential backoff (BEB) to mediate access to the channel. One of the main challenges in these MAC protocols is their vulnerability to signal jamming attacks [1]. This vulnerability emanates from their shared-access nature, which allows malicious adversaries to bottleneck the channel using off-the-shelf hardware [2]. Other types of networks that use a different topology, such as mesh topology, require more jamming resources than MAC networks. These networks use more than one shared medium, which complicates the jamming attack [3, 4]. A malicious node can simply jam the network via signal transmission on the shared channel. This jamming attack causes transmitted network packets to be garbled which prevents communication between the nodes. While the BEB algorithm achieves reasonable throughput and average latency in non-adversarial settings, its performance degrades when the shared medium is exposed to signal jamming attacks, especially when the number of nodes on the shared channel is high. Many researchers have focused ondevising methods to improve the jamming resistance of MAC networks. Some of these approaches are ineffective, which only works for low jamming rates and reduces the network's transmission rate. Other methods can cause significant packet delays, such as channel hopping [5; 6; 7; 8; 9]. WLANs also suffer from severe performance bottlenecks when a huge number of nodes contend for access to the channel [10; 11; 12; 13]. The throughput of the network degrades significantly for large networks. This degradation affects communications, especially in places with a typically large number of nodes such as conference venues and public hotspots. The broadcast algorithm is one of the main factors affecting the performance of WLANs. Other problems impairing WLANs performance include intercell interference and network traffic overhead caused by the change in AP association [14; 15]. In this work, we attempt to address one of the performance issues by proposing a new jamming-resilient broadcast algorithm that is more efficient than the standard BEB algorithm. This paper explores a different direction: improving MAC network performance and resilience to jamming attacks by replacing the BEB algorithm with a more jamming-resistant broadcast algorithm. To this aim, we propose a new broadcast algorithm called the K-tuple full withholding (KTFW) algorithm. The BEB algorithm relies on randomness to avoid collision of retransmission packets, whereas our algorithm manages access to the channel in a deterministic manner. Although the KTFW algorithm is deterministic, it does not require a central node, and the algorithm is executed in a distributed manner by all the nodes. The KTFW algorithm is designed specifically for MACs with collision detection capability. Although existing WLANs do not have collision detection, research has been done on providing collision detection capability for WLANs [16; 17; 18]. We model the attack as a random (also called memoryless) jammer that corrupts transmitted packets with a certain jamming rate between 0 and 1, where 0 means no jamming and 1 represents continuous jamming.