Features of collision avoidance in wireless networks

Collision avoidance refers to the methods and systems . It is used to prevent collisions between objects or entities commonly used in various fields .

Collision cannot be detected in hidden node problem

 

The “hidden node problem” is a challenge in wireless networking particularly in scenarios where nodes in a network cannot directly detect each other. This issue primarily occurs in wireless communication systems, especially in environments using the CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) protocol, commonly seen in Wi-Fi networks.

In this problem, nodes within a network may be out of range or obstructed from detecting one another due to physical barriers or distance. As a result, a transmitting node might be unaware of other nodes transmitting within the same network. When multiple nodes transmit data simultaneously, it leads to interference or collisions at the receiving nodes.

Typically, collision detection in networking relies on nodes being able to sense whether the medium (the wireless channel) is busy before transmitting data. However, in the hidden node problem, due to the inability of nodes to detect each other, collisions might occur as multiple nodes might start transmitting data simultaneously, unaware of each other’s activity.

collision avoidance in wireless networks

Carrier Sense Multiple Access with Collision Avoidance

(CSMA/CA): This is a protocol used in wireless networks to prevent data collisions. CSMA/CA ensures that a device checks for the presence of other signals before transmitting data, thus reducing the risk of collisions.

Clear Channel Assessment (CCA)

CCA is a mechanism used to determine whether a wireless channel is clear or busy before transmitting data. This feature helps to avoid collisions by ensuring that a device does not transmit data when the channel is already in use.

Request to Send (RTS) and Clear to Send (CTS)

RTS and CTS are signals that are sent between devices to reserve a channel for data transmission. These signals help to prevent collisions by ensuring that only one device transmits data at a time.

Collision Detection

In cases where collisions do occur, collision detection helps to reduce their impact by allowing the devices to detect and retransmit the data.

Quality of Service (QoS)

QoS is a mechanism that prioritizes traffic based on its importance or urgency. By assigning different levels of priority to different types of traffic, QoS can help prevent collisions by ensuring that important traffic gets transmitted first, reducing the risk of collisions with less important traffic.

Fragmentation

Fragmentation is the process of breaking up large packets of data into smaller fragments before transmitting them. This helps to prevent collisions by reducing the amount of time that any one device is transmitting data, allowing other devices to access the channel more frequently.

Power Control

Power control is a feature that adjusts the power level of a wireless device based on its distance from the access point. By reducing the power level of devices that are close to the access point, power control can help prevent collisions by reducing the risk of interference with other devices on the network.

Interference Avoidance

Interference avoidance is a mechanism that identifies sources of interference on a wireless network and takes steps to avoid them. By avoiding sources of interference, such as other wireless networks or electronic devices, interference avoidance can help prevent collisions by reducing the risk of signal degradation or loss.

Channel Bonding

Channel bonding is the process of combining multiple wireless channels into a single, wider channel. By using channel bonding, wireless networks can increase their bandwidth and reduce the risk of collisions by allowing multiple devices to transmit data simultaneously on different channels.

Pros of collision avoidance in wireless network

• Enhanced Throughput: By minimizing collisions, more data packets can be successfully transmitted within a given timeframe, improving overall network throughput.
• Reduced Retransmissions: Collisions often lead to packet loss, requiring retransmissions. Collision avoidance decreases such instances, reducing the need for redundant data retransmission and optimizing network efficiency.
• Improved Latency: With fewer collisions and retransmissions, latency decreases as data packets reach their intended destinations more promptly, benefiting real-time applications like video streaming or online gaming.
• Better Scalability: As network traffic grows or more devices join the network, collision avoidance mechanisms facilitate smoother communication and prevent congestion, thereby ensuring scalability without compromising performance.
• Increased Reliability: Minimizing collisions enhances the reliability of data transmission, reducing the likelihood of data corruption or loss, which is crucial for critical applications and sensitive data transfer.
• Fair Access: Collision avoidance methods promote fair access to the communication medium, allowing all devices in the network an equitable chance to transmit data without one device monopolizing the channel.
• Optimized Power Consumption: By avoiding collisions and retransmissions, devices can conserve energy as they don’t have to engage in unnecessary data retransmission attempts, leading to more efficient power usage.
• Compatibility and Standardization: Most collision avoidance techniques adhere to standard protocols, ensuring compatibility between various devices and networks following the same standards, promoting seamless communication.

Cons of collision avoidance in wireless networks

• Increased latency: Collision avoidance protocols like CSMA/CA introduce latency into the network, as devices have to wait for their turn to transmit data. This can lead to slower data transmission and increased response times.
• Network overhead: Collision avoidance protocols require additional signaling between devices, which can increase network overhead and reduce overall network efficiency.
• Limited scalability: Collision avoidance protocols like CSMA/CA may not scale well in larger networks with many devices. As the number of devices increases, the likelihood of collisions also increases, leading to decreased network efficiency.
• Complexity: Implementing collision avoidance protocols can be complex and require additional hardware and software resources. This can make it more challenging to manage and troubleshoot network issues.

Conclusion