# Intelligent Video Surveillance Platform for Wireless Multimedia Sensor Networks
## 2 Related Work
CODA proposes closed loop multi-source regulation technique and an open loop hop-by-hop backpressure strategy. Fusion uses prioritized MAC, hop-by-hop, and rate-limiting flow control methods to ease congestion [32]. Fusion has better fairness and higher goodput with heavy loads than previous techniques. Unlike CODA, Fusion explicitly focuses on per-source fairness. Our previous work, enhanced congestion detection and avoidance (ECODA), uses dual buffer-based congestion detection method [33]. ECODA discriminates route through traffic and locally generated traffic for the queue control. In ECODA, packets are dropped according to their priorities to control congestion. Both congestion control and fairness (CCF) [34] routing scheme and interference-aware fair control (IFRC) [35] protocols provide fairness. CCF presents two schemes to ensure fairness. One is epoch-based proportional selection and other is probabilistic selection. IFRC employs multi-level buffer threshold. When buffer occupancy goes beyond certain limit, IFRC reduces the sending rate and sustains its buffer occupancy at less than certain limit. [PERSON] et al. [36] propose congestion control protocol for WMSNs (WCCP). WCCP uses Recipient Congestion Control Protocol (RCCCP) at the intermediate nodes and the Source Congestion Avoidance Protocol (SCAP) at the source nodes. RCCCP uses buffer length to detect congestion, while SCAP uses group of pictures (GOP) to avoid congestion. In addition, WCCP protects only I-frame data packets and discards less important data packets in congestion situation. [PERSON] et al. [37] propose hierarchical tree alternative path scheme for WSNs (HTAP).Their work provides reliability and minimizes congestion by giving information to other nodes about congestion. When congestion is imminent, HTAP securely transmit the data by creating substitute routes from source to destination. HTAP algorithm consists of four major parts: Alternative Path Creation Algorithm, Flooding with Level Discovery Functionality, Alternative Path Creation Algorithm, The Hierarchical Tree Algorithm, and the Handling of Powerless (Dead Nodes). Siphon [38] provides congestion avoidance, congestion detection, and application fidelity by using virtual sinks (VSs) with multiple radios in the sensor network. VSs tunnel traffic events that show the signs of high traffic loads. Siphon employs a combination of end-to-end and hop-by-hop congestion control based on the location of congestion. In congestion situation, Siphon adopts the end-to-end congestion control approach between the virtual sinks and sink, and hop-by-hop method between source nodes and the virtual sinks. [PERSON] et al. [39] propose a dynamic and distributed hop-by-hop congestion control scheme to control congestion by adjusting data rate of nodes. They use virtual gradient field to provide a trade-off between possible shortest path and congested path. [PERSON] et al. [40] propose a dynamic alternative path selection scheme for wireless sensor networks (DAIPaS). DAIPaS uses channel interference, node energy, and buffer occupancy to detect congestion. It dynamically routes the traffic and selects the shortest path to avoid congestion. DAIPaS consists of two stages: hard stage and soft stage. In the hard stage, the network protects the receiving node from congestion by forcing the flows to change their paths. In the soft stage, each node receives data from only one stream to avoid congestion. [PERSON] et al. [41] present a distributed congestion control algorithm that adaptively assigns a fair and efficient transmission rate to all nodes. Each node monitors and controls its aggregate input and output traffic rate. A node decides to increase or decrease the bandwidth based on the difference between input and output traffic rates. The main idea of above mentioned researchers was to classify the priority of the packets and guarantee the transmission of these packets by the resource assignment.