User's Manual
Table Of Contents
- Health Limits
- Contents
- Before You Begin
- Developing the Installation Site Plan
- Installing and Configuring the MPI 6000
- Lane Tuning Guidelines
- Optimizing MPI 6000 Reader System Performance
- General Software Information
- Configuration Commands and Responses
- Configuring the MPI 6000
- Required Commands to Set Up MPI 6000 Reader
- System Interface Command Group Commands
- System Identify
- Set Communications Baud Rate
- Get Communications Baud Rate
- Set Time and Date
- Get Time and Date
- Firmware Download
- Reset Reader
- Get Stored Tag Response Message
- Get Number of Stored Tag Response Messages
- Delete All Stored Tag Response Messages
- Get System Startup Status
- Get Lane Controller Interface Status
- Get System Interface Status
- Get DigBrd Hdwr Remote Inventory
- Get DigBrd CPU Boot Fmwr Remote Inventory
- Get DigBrd CPU Appl Fmwr Remote Inventory
- Get DigBrd FPGA UDP/IP Core Fmwr Remote Inventory
- Get UDP/IP Core Lane Controller Parameters
- Set UDP/IP Core IP Address
- Get UDP/IP Core IP Address
- Get UDP/IP Core Port Number
- Configuring the MPI 6000
- Tag Command Processing
- System Diagnostics and Preventive Maintenance
- Acronyms and Glossary
- Block Diagrams
- System Technical Specifications
- Hardware Interfaces
5-3
Chapter 5
Optimizing MPI 6000 Reader System
Performance
This chapter provides information to optimize the MPI 6000 performance
and reduce cross-lane interference.
Cross-Lane Interference in RFID Systems
Radio frequency identification (RFID) systems are subject to various types of interfer-
ence that can affect the level of communications between a tag and a reader system. A
type of interference that can result from the operation of the reader system is called
cross-lane interference.
What Is Cross-Lane Interference?
Cross-lane interference occurs when the RF generated in one toll lane interrupts the
RFID operation in another lane that causes the affected lane to perform poorly. Before
diagnosing cross-lane interference, it is necessary to understand what constitutes a sat
-
isfactorily performing lane.
Determining Acceptable Lane Performance
The criteria for optimal lane performance are usually set by the customer and can vary
according to the site requirements. In testing, acceptable lane operation criteria typi
-
cally are determined by the length of the RF footprint and the speed of the test vehicle.
Usually, a test vehicle’s speed is limited by the amount of the toll lane that can be used
for starting and stopping distances. Usually, testing speed is limited to 20 miles per
hour (mph) or 32 kilometers per hour (kph) or less.
An ideally performing toll lane will produce one handshake for every 4 milliseconds
of transaction time. At 20 mph (32 kph), the vehicle uses 34 milliseconds to travel
through 1.0 foot (0.3 m) of the footprint. If the footprint is 8 feet (2.4 m), this means
that the vehicle will spend approximately 272 milliseconds in the footprint. Based on a
vehicle speed of 20 mph (32 kph) and an 8-foot (2.4m) footprint, this yields an ideal
maximum number of 68 handshakes. Nulls and voids within the RF footprint will
lower this number, as will any other local sources of RF noise and stray reflections. A
rule of thumb for lane performance is to have 40 to 60 handshakes within an 8-foot
(2.4m) footprint with a test vehicle traveling at 20 mph (32 kph). A system that oper
-
ates with less than 40 handshakes should be tested for cross-lane interference.