Designing wireless local area networking (WLAN) capabilities into stationary customer electronics (CE) systems is most successful when certain design issues are considered early in the development cycle.
W H I T E P A P E R
CE WLAN
By Steve SchnierCE WLAN Product WLAN Design Considerations Marketing ManagerSSchnier@ti.com For Stationary CE Applications Based on
Texas Instruments' Media Processors
Introduction Every application has certain design considerations that are particular to it. BecauseDesigning wireless local area net- of the size of the enclosure or the nature of the application, stationary CE products
working (WLAN) capabilities into usually stay in one place for long periods of time. Examples include media adapters,personal video recorders, certain high-end gaming consoles and IP (Internet Protocol)stationary consumer electronics (CE) set-top-boxes (STB). These types of systems operate off of power supplied by thesystems is most successful when power grid, and not batteries. The design considerations outlined here reflect the waycertain design issues are considered stationary CE systems are installed and how they function in the typical home. early in the development cycle. Doing References are made throughout this paper to the comprehensive design supportso at the front-end of design will that TI provides. Drawing on its years of experience in wireless technologies and
improve WLAN and host system embedded subsystems, TI has assembled the industry's most complete support programs and design documentation for WLAN applications. This level of supportperformance. This white paper lists vastly accelerates the integration of effective WLAN capabilities into stationary some of the most critical design con- CE products, allowing manufacturers to concentrate on developing differentiatedsiderations for integrating Texas functionality for their products, which makes these products more competitive in Instruments (TI's) WLAN solutions into the marketplace.
host systems based on the DaVinciT System-Level Considerationsand digital media (DM) processors. WLAN implementations should optimize certain basic performance parameters within the context and constraints of the application. These parameters include thereach or range of WLAN signaling, the data throughput rate supported by the WLANimplementation and its robustness when it comes to overcoming various sources ofinterference in the environment. In addition, the selection of a WLAN chipset solution as well as the software environment and tools supported by the WLAN solution are also important considerations.
Reach, Rate and RobustnessThe effective reach or range of WLAN signaling is often determined by the specificrequirements of the application. Some stationary CE systems require "whole house"coverage, while others do not. The effective reach of WLAN signaling is affected bythe system's transmit output power and the sensitivity of the WLAN receivers. Forstationary CE systems, which usually have access to a constant supply of power, out-put power can be adjusted upward somewhat to achieve greater range. Receiver sen-sitivity is an inherent capability of the WLAN chipset, and so careful attention should be2 Texas Instruments
paid to this feature. A general rule of thumb is that for every 6 dBm increase in receiver sensi-tivity, there is roughly double the linear range in free space. For example, a WLAN subsystemthat has a sensitivity of -76 dBm at 54O FDM has roughly twice the linear range and 4 timesthe coverage area (in free space) as a chipset that has a sensitivity of -70 dBm at 54O FDM.
G++ Technology
G++T Technology
High data throughput speeds are certainly important for some stationary CE applications,as is the ability to connect at large distances. System-level design decisions and thethroughput rate of the WLAN chipsets have a decided impact on these factors. Robustness of a WLAN implementation can be of particular importance in stationary CE systems which are often subjected to several sources of adjacent channel and in-bandinterference. The sources of interference commonly found in homes include microwaveovens, cordless telephones and other WLAN networks in close proximity. The inherentcapabilities of the WLAN chipset as well as antenna placement and other design considerations can increase or decrease the robustness of a stationary CE product withWLAN capabilities.
Chipset SelectionThe processing requirements of the host processor demanded by the WLAN chipset willhave significant effects on the overall perform... [download for more]
