1 Introduction
-
The number of channels assigned to a node must be equal or less than the number of radio interfaces it has.
-
The neighboring nodes must have at least a radio at a common channel to be able to communicate with each other.
2 Simulation components for multi-radio mesh networks
2.1 Multi-radio wireless nodes
Parameter name | Description | Sample value |
---|---|---|
Standard | MAC and physical layer standard | ns3::WIFI_PHY_STANDARD_80211a |
PropagationDelay | The propagation delay between the specified source and destination | ns3::ConstantSpeedPropagationDelayModel |
PropagationLoss | Modalize the propagation loss through a transmission medium | ns3::RangePropagationLossModel |
MaxRange | Radio range | 250 m |
RemoteStationManager | Data and control packets transmission rate | ns3::ConstantRateWifiManager |
2.2 Network devices
2.2.1 Configuring the radio interface
2.2.2 Data service components
-
The number of radio interfaces a node has
-
The channel assigned to each radio interface
-
At which time each node will switch from one channel to another
-
At which time each node can receive packets on each channel.
Element | Description |
---|---|
Packet type | The type of the packet: data or control |
Packet | A pointer to the packet |
Expire time | The time at which the packet expires and should be |
dropped |
2.3 External interference and channel sensing
2.4 Routing modifications
-
Sequence number
-
Node ID of the source
-
Node ID of the destination
-
Node ID of the next hop device to the destination
-
The time of originating the packet.
2.5 Synchronization
3 An example of CA implementation: SICA
3.1 External interference estimation
3.2 Channel selection mechanism
3.3 Control packet elements
3.4 Data and control transmission
-
The channel is being sensed by any of the neighbors.
-
The channel is busy due to the external interference.
-
The T interface did not switch to the channel successfully.
-
The estimated transmission time is less than the remaining time over the current channel.
4 Validating the game model
5 Verifying the simulation model
-
The frequency channel it is using
-
The number of packets it has received
-
The number of packets it has sent
-
The number of packets it has dropped.
-
Sending a packet (Send, unconditional event)
-
Receiving a packet (Receive, conditional, )
-
Dropping a packet (Drop, conditional, )
-
Changing the channel of the radio interface (Channel Change, unconditional event).
-
Only one channel must be assigned to a radio. In a hybrid CA, after assigning a channel to a radio, the radio may not switch immediately to the new channel since the node must inform the neighbors about the upcoming switching. Moreover, if a radio is receiving data, the node will not switch until the end of the data transmission. Therefore, CA must avoid assigning a new channel to a radio before the previous channel assignation took effect.
-
There must be a common channel between the sender radio and the receiver radio at any given time. In dynamic and hybrid CAs, the data transmission mechanism must be sure that the radios of the nodes are tuned to the same channel before the transmission starts. This must be achieved through an appropriate synchronization and switching mechanism.