Four main design requirements for WLAN solution

Four main design requirements for WLAN solution are:

• Scalability   

  To achieve the scalability, WLAN must be configured in a variety of topologies to meet the needs of specific applications and end users. WLAN has to be easily reconfigured from peer-to-peer networks for a small group of users to vast infrastructure networks of thousands of users that can roam across the areas. Speed and distance are also paramount factors in scalability of a WLAN. When organization grows, more users will get connected to the network. In addition, it is very likely that we need more bandwidth for transferring of larger files, streaming audio/video, and faster speed for real-time conferencing. Distance range can also be a factor in the scalability of the WLAN. New deployment of access points is demanded if the area of office is physically expanded.

• Manageability   

  To achieve the manageability of WLAN, network should be effectively managed; otherwise the benefits that brought by WLAN will quickly diminish and become more of a cost burden than savings. Effective and robust WLAN management software gives network administrators the ability to maximize the performance of network, and to make the WLAN as secure as possible. For example, WLAN management software can monitor every access point in the network from time to time, giving an instant feedback so that the network administrator can immediately adjust the WLAN connection and mitigate the network load.

• Interoperability  

  To achieve the interoperability for WLAN solution, the underlying heterogeneous components should be able to be integrated. The interoperability depends on technology choice and on the specific manufacturer’s implementation. If different manufacturers using the same technology and implementation for their own products, typically the interchange of adapters and access points is allowed. While designing a WLAN, it should be compliant with existing network infrastructure and configuration software, to order to make upgrades easier for system integrators in future.

• Availability  

  To achieve the possible availability, decent processes should be implemented for all aspects of the network, such as software, hardware, security, applications and networking. Availability can be maintained through the proper design of security and network management. In addition, certain automated features can be utilized to reduce errors triggered by human, and to prevent potential failures and minimize the downtime.

Productivity benefits can be achieved if a WLAN were to be implemented in the job industry

The WLAN brings significant benefits such as flexibility, mobility and portability to users. WLAN provides employees in the job industry the mobility to work virtually anywhere in their work area, their desk, conference room, or even multi-story office. This flexibility supports productivity and service opportunities; and far outweighs the wired networks. Deployment of WLAN components is very easy and no pulling cable through walls and ceilings is needed.

WLAN increases employee productivity, lower the organization operational costs and facilitate applications like mobile POS (Point of Sale) terminals and Voice over wireless LAN (VoWLAN). By using the VoWLAN, employees are able to make outgoing calls and receive incoming calls with an IP or cellular network, communicate with others by using messages, gain high-speed access to shared information.

The following are some of the productivity benefits can be possibly achieved through the power and flexibility of WLAN:

• In the hospital, doctor can instantly deliver patient information to the nurse by using handheld or notebook computers with WLAN capability
• Staffs at hotels use WLAN connectivity to facilitate access to shared information and information exchanges. They are more productive because they can instantly obtain guest information from the front desk.
• Retail store staffs use mobile POS terminals to simply connect to POS application system and place an order, check inventory status. This helps them to save time and to be more productive. 
• Warehouse workers could increase their productivity by using WLAN to connect to central databases for exchange of information.
• Senior executives in conference rooms able to make decision quickly and precisely as they have real-time information while using WLAN connection.

Some operating and environmental conditions that need to be considered in the WLAN site survey

When conducting a site survey, several paramount factors that may affect the performance of the WLAN must be thoroughly considered.

If we are going to install the WLAN in a building, we should know whether they are many walls or large structures or any types of obstacles to block the RF signal. Where will the network to be installed, in an open environment or closed environment such as building or office. Some environments that contain certain object such as large filing cabinets, concrete pillars, steel beams and even heavy machinery may reduce the range of wireless access points. The amount of RF interference (RFI) and electromagnetic interference (EMI) are actually present and paramount. Some environments that include cordless phones, electronic devices, microwave ovens could degrade WLAN performance must also be considered.

Identifying AP locations and the antennas to be used is very important in a site survey. To provide seamless Radio Frequency (RF) coverage for WLAN, APs must be positioned with wide enough overlapping coverage to ensure there are no gaps, or dead spots within the coverage area. We must also identify the areas where additional APs, antennas or repeaters may be needed to overcome interferences, signal loss or range problems.

RF signals transmit and broadcast through the air are subject to attenuation, signal strength loses while encountering obstacles. The distance between the AP and client affects WLAN bandwidth and therefore capacity. The distance between client’s device and AP increases, the signal strength will then decrease. In this case, the bandwidth has to decrease to maintain the connection. The channel assignments for APs will need to be far enough apart to avoid inter-access point interference.

We cannot determine exactly the overall effect of all the objects in most sites if we do not do the testing and verification as the actual attenuation will vary widely.