ZigBee is a wireless standard for personal area network (PAN) sensor monitoring and control. National Instruments' Alliance Partner SeaSolve has developed a test suite including transmit (Tx), receive (Rx) and compliance testing for ZigBee. In this two-part article, we will describe test methodologies and techniques for each type of testing.

Part 1 introduced ZigBee testing requirements and focused on transmitters. This part looks at receivers, frame types, and compliance testing.

ZigBee Receiver Testing
The requirements for testing a ZigBee receiver can generally be broken into two requirements: media access control (MAC) layer emulation and impairments testing at the physical layer (PHY). The first type, MAC layer emulation, can be used to ensure that the ZigBee receiver is able to respond appropriately to the generated commands. With the second type, impairments testing, a receiver is tested by intentionally reducing the modulation quality of the test stimulus. The examples below use SeaSolve's WiPAN LVSG signal generation solution combined with a PXI vector signal generator, as illustrated in the Figure 8.

8. WiPAN mapping on ZigBee protocol stack.

In Figure 8, we have illustrated that the IEEE 802.15.4 standard defines the MAC and PHY layers of a ZigBee transmissions. Typical test procedures involve both MAC layer emulation through packet generation and PHY layer testing by adding impairments.

ZigBee Frame Types
The MAC (Media Access Control) layer of a ZigBee transmission defines the basic packet and frame structures. The IEEE 802.15.4 specification defines four basic frame structures that can be used for receiver test. These frame types include:

• A beacon frame is used by a coordinator to transmit beacons. The beacon packet enables a node to identify the presence of other nearby
• A data frame, is used for all transfers of data payloads
• An acknowledgment frame is used for confirmation of a successful frame reception
• MAC command frame is used to handle MAC peer-entity control transfers

The MAC command frame is the most flexible. Thus, receiver testing also involves selection of specific sub-frames, listed by type, below:

1. Association request is a request for association with a PAN coordinator.
2. Association response is a reply from coordinator with association status (possibilities include: Association Successful, PAN at capacity, Access denied)
3. Disassociation notification is used by device or coordinator to inform other nodes about disassociation.
4. Data requestis used to request data from a coordinator.
5. PAN ID conflict notification is transmitted when a PAN identifier conflict is detected
6. Orphan notification is used by an associated device that has lost synchronization with its coordinator
7. Beacon request