## 2 Related Work
### Distributed Algorithms  
Pulse [19] is a distributed anti-collision protocol that utilizes a control channel for exchanging notifications between readers. When it comes to tag interrogation, Pulse employs a single data channel. The reader currently engaged in tag reading broadcasts a beacon to prevent neighboring readers from utilizing the active channel. However, in dense RFID networks, this approach leads to the disabling of many readers, resulting in a degradation of system performance.  
To address this problem, the MCMAC (Multi-Channel MAC) [20] protocol is introduced. MCMAC allows RFID readers to manage multiple data channels at the MAC layer. Readers use the control channel to announce the occupied frequencies to their neighboring readers, enabling more efficient utilization of resources.  
Another distributed TDMA-based protocol, known as Distributed Efficient & Fair Anti-Collision (DEFAR) [21], aims to select at least one reader within a collision domain. It achieves this by exchanging beacons between readers, effectively reducing both monochannel and multi-channel collisions. Priorities are assigned to readers based on their behavior compared to previous states, enabling the selection of a reader based on its identification and priority level.  
For mobile dense and time-critical deployments in RFID networks, Coverage Oriented Reader Anti-Collision (CORA) [22] provides a reciprocal local solution. Each reader depends on its neighborhood for activation, allowing for identification of colliding neighbors. CORA relies on local learning within each reader's neighborhood.  
HAMAC (High Adaptive MAC) [23] is a dedicated protocol designed for mobile and large-scale RFID networks. Based on CSMA (Carrier Sense Multiple Access), HAMAC dynamically controls window contention to avoid collisions in the WSN (Wireless Sensor Network). It adjusts its contention window based on network congestion on available frequencies, employing either linear or multiplicative decreasing mechanisms.  
Frequency Time Scheme MAC (FTSMAC) [24] is a distributed RFID anti-collision protocol that employs a special notification system for distributing frequency resources. The first reader to wake up initiates the process of discovering neighboring readers for frequency reuse, and this discovery process continues. Readers within the same data channel group query tags simultaneously during assigned time slots.  
DMLAR (Distributed Machine Learning-Based Anti-Collision for Readers) [25] is an innovative anti-collision algorithm designed for RFID readers operating in mobile environments. It offers individual resource control using learned collision prediction models for both Reader-to-Reader and Reader-to-Tag interferences. The dataset continuously updates with each reader movement, and upon simulation completion, readers broadcast their datasets to establish a comprehensive database. The primary objective is to enable collision-free tag interrogation, autonomously improving the efficiency of mobile RFID networks.  
DPCPCPSO (Distributed Parallel Cooperative Co-evolution Particle Swarm Optimization) [26] presents an enhanced RFID reader anticollision model, which addresses challenges by modifying the measure index, introducing a constraint function, and considering collisions among readers and between readers and tags. The dense deployment of numerous readers leads to a high-dimensional problem, unsolvable by traditional algorithms. Hence, distributed parallel cooperative co-evolution particle swarm optimization (DPC-CPSO) is introduced, dynamically adjusting the inertia weight and learning factors during evolution and presenting an improved grouping strategy.