09-03-2011, 10:34 AM
Presented By
MANOJ SUDHARSHAN J
[attachment=9833]
Congestion Control for Efficient Transmission in ZigBee Networks
INTRODUCTION
ZigBee is a leading wireless network technology with low cost, low power based on IEEE 802.15.4
Recently, ZigBee networks are rapidly developed because of its low cost, low power and high reliability characteristic
Congestion control is necessary technique in order to guarantee a reliable transmission and network efficiency
ZigBee provides retransmission and acknowledgment (ACK) to prevent data loss instead of congestion control. It could prevent congestion situation rather than control it.
When congestion occurs there is no mechanism to control it in ZigBee. Only using retransmission and ACK, ZigBee prevents congestion
NEED OF ZIGBEE
Installation cost
Maintenance
New markets
ZIGBEE BENEFITS
Low Cost
Range and obstruction issues avoidance
Multisource products
Low power consumption
STACK ARCHITECTURE OF ZIGBEE PROTOCOL
Network and Application Support layer
Physical (PHY) layer
Media access control (MAC) layer
ZIGBEE DEVICE TYPES
The ZigBee coordinator node
The full function device FFD
The reduced function device RFD
NETWORK LAYER AND TOPOLOGY OF ZIGBEE
The Zigbee network layer (NWK) supports star, tree and mesh topologies
• Modes of Traffic in Zigbee
ZigBee employs either of two modes to enable the to-and- fro data traffic
1. Beacon Mode
2. Non-Beacon Mode
CURRENT ZIGBEE TECHNOLOGY
In Zigbee technology each node forms the topology and network configuration. Thus each node can freely send and receive data.
All collected data will be sent to the sink node. Getting closer to the sink node, network traffic will increase.
Also ZigBee networks provide the ACK and retransmission functions to ensure the reliability of data. These functions are kind of congestion avoidance
• Successful data transmission with an ACK
• Retransmissions are failed – The worst case
PROPOSED CONGESTION CONTROL
1. ZCCF (ZigBee Congestion Control Frame)
Network Congestion Case # 1 Network Congestion Case # 2
2. ZTCC (ZigBee Time Congestion Control)
When the originator receives ‘Congestion reply command’ or ‘Congestion announce command’, a transmission time is increased as shown in (1) below. We define the time value-apscThresholdTime.
After apsCongestionTime value is greater than the threshold value, it will be increased linearly as shown in (2).
apsCongestionTime = apsCongestionTime • 2. (1)
apscThresholdTime = apscThresholdTime + 20. (2)
To stabilize the networks, we use the ACK Command
When the originator receives the ACK, it confirms congestion bit. If the congestion bit is 1, the originator will changes a transmission time as shown in (3) and a threshold time value as shown in (4).
apsCongestionTime = apsCongestionTime / 2. (3)
apscThresholdTime = apscThresholdTime – 100. (4)
As a result, when congestion situation is over, a data transmission time is returned to the original value. The threshold time is back to the default value after 5 continuous ACKs
SIMULATION RESULTS
The compartment of the ZBN and CCZ in the many-to-one communication application is shown.
As shown in Fig, as the number of nodes increases, CCZ acquires performance of less transmission time than the ZBN when transmitting 50Kbytes data.
The period of the whole communication is considered as the transmission time.
When the quantity of nodes is equal 100, by the use proposed congestion control, the CCZ network speed is improved about 9.31% than the ZBN.
The simulation results show us that the proposed ZigBee APS layer has a performance improvement.
GENERAL CHARACTERISTICS OF ZIGBEE
• Data rates from 20 to 250 kbps
• Star Topology/Peer to Peer (mesh)
• 255 devices / network
• CSMA-CA Access Scheme
• Enumeration (new node) ~ 15-30 ms
• Dual PHY (868/915 MHz, 2.4 GHz), DSSS
• Range: 10-100 m
• Low Duty Cycle (< 0 .1%, TX)
• Low Power Cons, +1 year battery life time
• Complexity: 4 -32 kB (protocol)
APPLICATIONS OF ZIGBEE
Home Entertainment and Control
Home Awareness
Mobile Services
Commercial Building
Industrial Plant
CONCLUSION
Zigbee provides a promising wireless network for a small area network
Zigbee provides an advantage of range and obstruction.
There are many standards like Bluetooth and Wi-Fi which provide mid and high data rates, but zigbee provides a unique network of low data rates and, cost effective radios and low power consumption circuits.
In reference to the ieee paper, we have confirmed that ZigBee does not provide separate congestion control yet.
When congestion occurs in ZigBee networks, unnecessary traffic as well as unreliable data transmission increases power consumption.
MANOJ SUDHARSHAN J
[attachment=9833]
Congestion Control for Efficient Transmission in ZigBee Networks
INTRODUCTION
ZigBee is a leading wireless network technology with low cost, low power based on IEEE 802.15.4
Recently, ZigBee networks are rapidly developed because of its low cost, low power and high reliability characteristic
Congestion control is necessary technique in order to guarantee a reliable transmission and network efficiency
ZigBee provides retransmission and acknowledgment (ACK) to prevent data loss instead of congestion control. It could prevent congestion situation rather than control it.
When congestion occurs there is no mechanism to control it in ZigBee. Only using retransmission and ACK, ZigBee prevents congestion
NEED OF ZIGBEE
Installation cost
Maintenance
New markets
ZIGBEE BENEFITS
Low Cost
Range and obstruction issues avoidance
Multisource products
Low power consumption
STACK ARCHITECTURE OF ZIGBEE PROTOCOL
Network and Application Support layer
Physical (PHY) layer
Media access control (MAC) layer
ZIGBEE DEVICE TYPES
The ZigBee coordinator node
The full function device FFD
The reduced function device RFD
NETWORK LAYER AND TOPOLOGY OF ZIGBEE
The Zigbee network layer (NWK) supports star, tree and mesh topologies
• Modes of Traffic in Zigbee
ZigBee employs either of two modes to enable the to-and- fro data traffic
1. Beacon Mode
2. Non-Beacon Mode
CURRENT ZIGBEE TECHNOLOGY
In Zigbee technology each node forms the topology and network configuration. Thus each node can freely send and receive data.
All collected data will be sent to the sink node. Getting closer to the sink node, network traffic will increase.
Also ZigBee networks provide the ACK and retransmission functions to ensure the reliability of data. These functions are kind of congestion avoidance
• Successful data transmission with an ACK
• Retransmissions are failed – The worst case
PROPOSED CONGESTION CONTROL
1. ZCCF (ZigBee Congestion Control Frame)
Network Congestion Case # 1 Network Congestion Case # 2
2. ZTCC (ZigBee Time Congestion Control)
When the originator receives ‘Congestion reply command’ or ‘Congestion announce command’, a transmission time is increased as shown in (1) below. We define the time value-apscThresholdTime.
After apsCongestionTime value is greater than the threshold value, it will be increased linearly as shown in (2).
apsCongestionTime = apsCongestionTime • 2. (1)
apscThresholdTime = apscThresholdTime + 20. (2)
To stabilize the networks, we use the ACK Command
When the originator receives the ACK, it confirms congestion bit. If the congestion bit is 1, the originator will changes a transmission time as shown in (3) and a threshold time value as shown in (4).
apsCongestionTime = apsCongestionTime / 2. (3)
apscThresholdTime = apscThresholdTime – 100. (4)
As a result, when congestion situation is over, a data transmission time is returned to the original value. The threshold time is back to the default value after 5 continuous ACKs
SIMULATION RESULTS
The compartment of the ZBN and CCZ in the many-to-one communication application is shown.
As shown in Fig, as the number of nodes increases, CCZ acquires performance of less transmission time than the ZBN when transmitting 50Kbytes data.
The period of the whole communication is considered as the transmission time.
When the quantity of nodes is equal 100, by the use proposed congestion control, the CCZ network speed is improved about 9.31% than the ZBN.
The simulation results show us that the proposed ZigBee APS layer has a performance improvement.
GENERAL CHARACTERISTICS OF ZIGBEE
• Data rates from 20 to 250 kbps
• Star Topology/Peer to Peer (mesh)
• 255 devices / network
• CSMA-CA Access Scheme
• Enumeration (new node) ~ 15-30 ms
• Dual PHY (868/915 MHz, 2.4 GHz), DSSS
• Range: 10-100 m
• Low Duty Cycle (< 0 .1%, TX)
• Low Power Cons, +1 year battery life time
• Complexity: 4 -32 kB (protocol)
APPLICATIONS OF ZIGBEE
Home Entertainment and Control
Home Awareness
Mobile Services
Commercial Building
Industrial Plant
CONCLUSION
Zigbee provides a promising wireless network for a small area network
Zigbee provides an advantage of range and obstruction.
There are many standards like Bluetooth and Wi-Fi which provide mid and high data rates, but zigbee provides a unique network of low data rates and, cost effective radios and low power consumption circuits.
In reference to the ieee paper, we have confirmed that ZigBee does not provide separate congestion control yet.
When congestion occurs in ZigBee networks, unnecessary traffic as well as unreliable data transmission increases power consumption.