BellHawk Store and Forward Technology

Two critical issues with tracking and traceability systems are:

Making sure that the data captured is correct.
Warning an employee when they are about to make an operational mistake.

This is straight forward when PCs connected to a local area network are used, as the PCs can access the central database to get validation data in real-time. Mobile computers used by mobile workers, however, present a more significant challenge.

For mobile workers, BellHawk uses an approach in which data validation is carried out against data in a local database on the mobile computer. This enables visual and audible warnings to be rapidly provided to the user before they make a mistake.

Transaction data is stored in non-volatile memory as it is captured and then relayed in real-time to the server as soon as the mobile computer can communicate with the server. If the mobile computer is not in communications range, then it automatically switches to "batch" mode and saves the data up until it is within communications range.

The benefit of this approach is that data capture can take place in communications blind spots, with automatic relaying of the data to the server when the mobile computer is in range. Also, data is retransmitted until the server has acknowledged its receipt, so as to avoid loss of data due to communications interference.

The data in the local database, used for data capture validation, is automatically updated whenever the mobile computer can communicate with the main server. This exchange of data, as well as the transmission of transaction data, takes place without user intervention.

The BellHawk BSAF (pronounced be-safe) store-and-forward data communications protocol works by securely exchanging UDP packets with a server at an IP (internet protocol) address. This enables mobile computers to be used for data collection and validation in remote facilities with communications taking place over low-cost Virtual Private Networks over the Internet.

The mobile computer periodically "pings" the server over the communications network. When it is able to communicate with the server then appropriate data objects are exchanged between the main server and the mobile computer. This is normally done over standard 802.11 b/g/n wireless communications networks but BellHawk can also be configured to work over cell-phone networks and other data networks.

BSAF can also be used in cradle-mode in those situations where wireless communications cannot be used due to security or safety (such as explosion) concerns. In this case the data objects are automatically exchanged between the mobile computer and the main server when the mobile computer is placed in a cradle attached to a PC that can access the main server.

Storing the data in a local database on each mobile computer enables BellHawk to be able to perform real-time point-of-action data validation even when the mobile computer is not in communication with the main server. This enables mobile computers to be used in environments, such as warehouses, manufacturing and processing facilities where it is difficult to maintain complete wireless communications coverage. It also enables BellHawk to be used in environments, such as yards and off-site warehouses. In these cases data is collected in the local database until the mobile computer is returned to an environment where there is communications coverage.

Wireless mobile computers, such as those used in BellHawk systems, normally use regular 802.11b/g/n WiFi communications protocols to communicate between the wireless mobile computers and wireless access points. With industrial mobile computers, such as those from Motorola, the open-air communications range is about 300 feet to an industrial access point, such as those from Cisco.

Unfortunately the radio waves are absorbed and scattered by conducting materials such as:

Metal racking in warehouses and stock rooms
Machinery and fork-lift trucks
Metal rebars and studs in walls
Metal pillars and roof joists
Metal products, drums and other conducting materials
People and other containers of liquid.

Also data transmission may be intermittently interrupted by electrical splash noise from welding and heavy electrical machinery. All of this makes factories, warehouses and industrial environments very challenging environments in which to achieve 100% wireless coverage at all times.

There are two approaches to using wireless mobile computers in an industrial setting:

Terminal mode - in which the mobile computer acts as a terminal to software that provides access to the central database system, either directly or through a web interface. In this mode, the mobile computer has to access the central database to perform point-of-action data validation.
Store and Forward mode - in which the mobile computer uses its local database to perform point-of-action data validation and capture until it can communicate with the main server, when it automatically exchanges data with the server.

In terminal server mode, continual wireless communications is required for point-of-action data validation. Also data entry response is slow due to the lag in communicating with the server (think Internet response). As a result material handlers can become very inefficient and become very frustrated due to data input that has to be repeated, slow response, and having to sometimes go to extreme lengths to validate a scanned barcode when in a communications "blind-spot".

With store and forward, all the transactions are stored up in a local database in the mobile computer until it is able to establish communications with the server via a wireless access point antenna. Then the data is automatically transferred to the server. As a result, material handlers can scan anytime and anywhere. They do not have to deal with "blind-spots" and resultant lost data or be held up due to slow response from the server. This makes for much more productive and happier personnel. Also because the mobile computer database is downloaded with all the data needed to check transactions in real-time, the incidence of mistakes is significantly reduced and most are corrected right away.

A major savings from BellHawk is that only a small number of access points are required to ensure adequate BSAF coverage in a warehouse or production area. Typically one Access point antenna is positioned over the loading dock area and another in a location frequently traversed by material handlers, such as the entrance to the production area. With BSAF it is typically not necessary to have coverage down the aisles of racking in a stock room or warehouse. Also its significantly reduces the need for radio frequency shielding from welding operations and heavy electrical machinery.

BSAF is fully automatic and requires no operator intervention. The communications protocol ensures that the data is stored away safely on the server's hard drive before it is removed from the mobile computer database. Also status data such as purchase orders, needed for assisting and validating operator inputs, are also downloaded automatically from the server in a similar manner.

Because BellHawk only communicates material movements to the Material Tracking Server through BSAF, the data link to the ERP system can be protected using appropriate firewall strategies. This is in contrast to a direct terminal server mode input to the ERP system, which is vulnerable to hacker attacks on the ERP system due to the direct communications between the wireless mobile computers and the ERP system.

Within BSAF, all communication between the wireless mobile computers is handled by the BellHawk Wireless Server program, which runs on the database server. This requires only one SQL Server client access license (CAL) irrespective of the number of wireless computers in use. This is in contrast to Terminal Mode systems where typically one CAL has to be purchased from Microsoft for each mobile computer in use.

In summary, the major benefits of the BellHawk Wireless BSAF approach are:

Scanning is never interrupted because of lack of wireless communications. Wireless MCs can be taken into the yard, to remote warehouse, and on truck delivery routes, and will synchronize their data again as soon as they can “see” a WiFi access point.
The risk of data loss is minimized as the data is stored until it has been verified to be safely stored on the server.
Data entry is rapid because all the data needed for validation is local to the mobile computer. Also the input data is stored locally in the MC enabling a user to be rapidly lead through data dependent scan sequences based on local rules in the MC.
Data can be extensively validated at the time of data entry because the MC has all the status data it needs for validation stored locally.
Only a limited number of access points are required at “choke points” through which mobile users frequently travel. This is in contrast to requiring a large number of access points to achieve “complete” wireless coverage.
Wireless BSAF only requires one server client license and one SQL Server client access license irrespective of the number of wireless devices being used.
Wireless BSAF is very secure as it only allows special encrypted BellHawk protocols to be exchanged with the server.