IEEE 802.15.4/ZigBee OPNET Simulation Model

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IEEE 802.15.4/ZigBee OPNET Simulation Model version 3.0 beta Overview of the simulation model of the IEEE 802.15.4 protocol The idea behind this simulation model was triggered by the need to build a very reliable model of the IEEE802.15.4/ZigBee protocols for Wireless Sensor Networks (WSNs). According to our personal experience, we strongly believe that the current version of the WPAN implementation in the Newtwork Simulator (ns-2) simulator is not accurate for the simulation of wireless sensor networks, even though existing modules can be reused in this context. Our OPNET simulation model implements more accurately the IEEE 802.15.4/ZigBee protocols without these unnecessary overheads, turning its results more reliable than those obtained with ns-2 or OPNET Modeler standard library. This is mainly due to the amount of additional overheads introduced by the ns-2 simulator, since it imposes the use of a UDP (User Datagram Protocol) agent in each node for generating data, and also the generation of ARP (Address Resolution Protocol) frames. In fact, ns-2 was originally developed for IP (Internet Protocol) networks and then extended for IEEE 802.11 wireless networks. Asa first step, we have developed a quite accurate simulation tool forthe IEEE 802.15.4 slotted CSMA/CA mechanism using OPNET Modeler simulator.In the next step, we have extended this simulation model about Guaranteed Time Slot (GTS) mechanism supporting deterministic real-time traffic. Then, we have implemented ZigBee network layer supporting cluster-tree topology and hierarchical tree routing (ZigBee's cluster-tree addressing scheme). Oursimulation model implements the physical layer of the IEEE 802.15.4 standard running at 2.4GHz Frequency band with 250 kbps data rate.The MAC layer supports the beacon-enabledmode and implements slotted CSMA/CA and GTS mechanism according to the standard specfication.There is also a battery module that computes the consumed and remainingenergy levels. The network layer implements hierachical tree routing according to the ZigBee standard. The application layer can generate best effort and/or real-time unacknowledged and/or acknowledged frames transmitted during Contention Access Period (CAP) or Contention Free Period (CFP) (contains GTSs) of the superframe, respectively. The sensor node model is composed of five functional blocks: The physical layer consists of a wireless transceiver (rx for reception and tx for transmission) compliant to the IEEE 802.15.4 specification operating at the 2.4 GHz frequency range with 250 kbps data rate. The modulation scheme is Quadrature Phase Shift Keying (QPSK). The MAC sub-layer implements the slotted CSMA/CA and GTS mechanism (e.g. GTS allocation, deallocation, and reallocation functions). The data traffic incomming from the network layer is stored in the buffers (one buffer for best effort (CAP) data and second one for real-time (GTS) data) and dispatched to the network when the corresponding Contention Access Period (CAP) or Guranteed Time Slot (GTS) is active. This module also controls the generation of the beacon, when the node acts as a PAN Coordinator. The network layer implements the hierarchical tree routing according to the ZigBee standard. The The application layer can generate best effort unacknowledged or acknowledged data frames transmitted during the CAP (using slotted CSMA/CA), and/or time critical unacknowledged or acknowledged data frames transmitted during the GTS. The battery module computes the consumed and remaining energy levels. The default values of current draws are set to those of the MICAz or TelosB mote specifications. Moreover, we use the default wireless models of OPNET library for emulating the background noise, propagation delay, radio interferences, received power, bit error rate, etc. In case of collisions, the reception result depends on the number of collided frames, received power and bit error threshold computed in the default receiver pipelines of the OPNET library. Supported (implemented) Features beacon-enabled mode (beacon frame generation) star-based, peer-to-peer and cluster-tree topologies slotted CSMA/CA MAC protocol different packet formats - directory packets (beacon, command, ack, MAC packet, PHY packet) physical layer characteristics computation of the power consumption (MICAz and TelosB (TmoteSky) motes supported) Guaranteed Time Slot (GTS) mechanism (GTS allocation, deallocation and reallocation functions) generation of the acknowledged or unacknowledged best effort application data (MAC Frame payload = MSDU) transmitted during the Contention Access period (CAP) generation of the acknowledged or unacknowledged real-time application data transmitted during the Contention Free Period (CFP) ZigBee network layer<\li> ZigBee hierarchichal tree routing verification of the nodes' addresses which must correspond to the ZigBee's cluster-tree addressing scheme Non-Supported Features Non beacon-enabled mode Unslotted CSMA/CA MAC protocol PAN management (orphan, join/leave, etc.) Installation Steps The IEEE 802.15.4 OPNET simulation model was developed and tested under the OPNET Modeler Wireless Suite provided under OPNET University Program licence. To install and run this simulation model in your computer, follow these steps (for simulation model version 2.1. and OPNET Modeler version 14.5): Intall the right version of the OPNET Modeler Wireless Suite and configure the environment, if you have not already done. Download the simulation model file and unzip it to any directory. Add this directory to the OPNET Model directories: File > Manage Model Files > Add Model Directory. The name of directory is automatically added to the environment database file: op_admin\env_db14.5. After this the directory name can be found in the Open file dialog: File > Open. Select appropriate Model Directory and File, and press Open. The default scenario contains one analyzer node (wpan_analyzer_node) and three sensor nodes (wpan_sensor_node) organized in a star-based topology. PAN_coordinator is star header and controls the network (e.g. enable/disable GTS mechanism, setting of BO, SO and PAN ID parameters for entire network). node_GTS generates only time critical traffic dipsatched during GTS. On the other side, node_CAP generates unacknowledged and acknowledged traffic dispatched during CAP. Additional nodes can be added from model repository: Topology > Open Object Palette > Node Models > Fixed Node Models > By Name > wpan. See video guide about how to set up the above mentioned network topology. Version History IEEE 802.15.4/ZigBee OPNET Simulation Model version 3.0 beta new structure of the node model ZigBee network layer hierachical tree routing verification of the nodes' addresses which must correspond to the ZigBee's cluster-tree addressing scheme IEEE 802.15.4 OPNET Simulation Model version 2.1 MAC frames (MPDU) are not dispatched direclty to the network but they are prefixed with PHY header (6 bytes) new packet formats for MSDU, MPDU and PPDU (see Data Units) only PPDU is dispatched to the network GTS Setting.Start Time parameter can be set to 0 sec - the dispatching of GTS request is postponed till beacon reception. acknowledgment mechanism for GTS transmission updated transaction-time checking mechanism (a device transmitting within the CAP/GTS shall ensure that its transaction is complete (i.e. including the reception of any acknowledgment) one IFS period before the end of the CAP/GTS). IEEE 802.15.4 OPNET Simulation Model version 2.0 added GTS mechanism GTS allocation, deallocation and reallocation functions in wpan_mac module GTS Traffic Source at the Application Layer generates unackowledged or acknowledged data frames transmitted during the CFP fixed a bug in wpan_backoff_delay_set() function backoff countdown was not paused at the end of the CAP fixed a predefined values of the Initial Energy attribute in Battery Module add TelosB (TmoteSky) current draw characteristics in Battery Module updated user-defined attributes updated a structure of the simulation model updated packet formats (beacon, command, ack, MAC_packet) update directories structure updated Traffic Source generator at the Application Layer independent parameters setting for generating acknowledged and unacknowledged data frames previous Sink module was improved and separeted into Traffic Sink and Synchro modules IEEE 802.15.4 OPNET Simulation Model version 1.0 beacon-enable mode beacon frame generation slotted CSMA/CA MAC protocol packet formats (beacon, command, data, ack, MAC_packet) computation of the power consumption (MICAz model supported) Downloads Package Version Date OPNET version Downloads OPNET Simulation Model 3.0 beta 20/11/2009 15.0 ZIP Video Guide * 2.1 31/03/2009 - AVI MPEG OPNET Simulation Model 2.1 31/03/2009 14.5 ZIP OPNET Simulation Model 2.0 22/05/2007 11.5 ZIP Reference Guide 2.0 22/05/2007 - PDF OPNET Simulation Model 1.0 06/04/2006 10.5 ZIP * MPEG mpeg2 codec, 720x576, size 44 MB AVI XviD codec, 720x576, size 14 MB Related References P. Jurcik, A. Koubâa, M. Alves, E. Tovar, Z. Hanzalek; A Simulation Model for the IEEE 802.15.4 Protocol: Delay/Throughput Evaluation of the GTS Mechanism; In Proc. of 15th IEEE International Symposium on Modeling, Analysis, and Simulation of Computer and Telecommunication Systems (MASCOTS07), Istanbul (Turkey), October 2007. A. Koubâa, M. Alves, B. Nefzi, Y. Q. Song; Improving the IEEE 802.15.4 Slotted CSMA/CA MAC for Time-Critical Events in Wireless Sensor Networks; In Proc. of the Workshop of Real-Time Networks (RTN 2006), Satellite Workshop to (ECRTS 2006), July 2006. A. Koubâa, M. Alves, E. Tovar; A Comprehensive Simulation Study of Slotted CSMA/CA for IEEE 802.15.4 Wireless Sensor Networks; In IEEE WFCS 2006, Torino (Italy), June 2006. A. Koubâa , M. Alves, E. Tovar; On the Performance Limits of Slotted CSMA/CA in IEEE 802.15.4 for Broadcast Transmissions in Wireless Sensor Networks; IPP-HURRAY Technical Report, HURRAY-TR-060401, Feb 2006.