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Hi-fidelity wireless for home networks

Posted: 01 May 2002 ?? ?Print Version ?Bookmark and Share

Keywords:wlan? home networking? portable device? pc? stb?

Today's home networking applications and services require a wireless protocol that enables multimedia-capable, easy to use, and reliable home networking products. In fact, the catalyst to driving mainstream home networking penetration and adoption is the ability to support entertainmentand communicationsoriented multimedia content. A primary driver for multimedia support in home networks is the proliferation of new digital consumer electronic devices.

But many of the technologies being used for home networking have simply migrated from the data-centric enterprise world. However, home users have a different set of requirements than enterprise users and products originally designed for the enterprise environment do not satisfy these requirements.

Networking perspectives

Home networking differs from enterprise networking in a variety of ways that influence the ultimate success of provided solutions. These differences include technical expertisenetworking knowledge in the home is minimal as opposed to a dedicated network administrator in the enterprise environment.

Applications for enterprise networking has typically focused on printer and file sharing among PCs, while applications for networking in the home are more entertainmentfocused and more likely tied to service provider offeringsmultimedia content distribution, broadband connection sharing, gaming, etc.

Devices supported in the enterprise environment consist of PCs and printers while the home environment is being bombarded with an assortment of digital devices that could potentially enjoy the benefits of a network: PCs, TVs, STBs, web pads, DVRs, etc.

A home network should have a home networking protocol, like Cirrus Logic's Whitecap2, specifically tailored for the home with three major criteria:

7 Multimedia and quality of service (QoS) support

7 Ease of use

7 System reliability

The wireless network protocol needs high performance, high network throughput and isochronous, multimedia-capable services, requirements not addressed by existing contention-based networking technologies found in the enterprise today.

QoS requirements

The ability to support multimedia is the "killer app" that will drive the mass adoption of home networks. Therefore, a home network must support the co-existence of batch data print jobs and file transfers and isochronous video, voice, audio content.

The protocol should provide superior throughput to support distribution of high-fidelity content, such as high bit-rate MPEG-2 (used in DVD titles and DVR video). Transmission in a data-oriented network (802.11b) faces pervasive skips and pauses. A dedicated protocol is needed to manage the transmission of such content at a higher bit-rate threshold and with higher quality.

A dynamic stream support function can utilize available bandwidth more efficiently than traditional 802.11 networks and provides for dynamic bandwidth allocation/management in an efficient manner. Allocation of network resources for each stream is based on bandwidth, latency and jitter requirements.

Ease of use

Without dedicated technical resources or administrative staff, a home networking protocol needs to be easy to use and maintain. A coordinator redundancy function enables continued operation even if the coordinator node within the network fails or is turned off by identifying alternate coordinators on the network and automatically transferring the coordination function to one of those nodes.

Home networks should ensure scalability to enable future growth for delivering consistently high-performance devices. Firmware upgrade, in some cases over the air, to support new network features and/or services is an important convenience feature.

Compliance with accepted and emerging standards is critical. Wi-Fi (802.11b) compliant-interoperability with other Wi-Fi devices/networks and forward interoperability path for compliance with 802.11e are the most important here.

Reliable wireless delivery

Delay sensitive streams such as video and audio cannot be retransmitted since a few dropped frames can severely diminish the quality and user experience. But a forward error correction (FEC) function can recover data "on the fly" and effectively increase the usable throughput.

A channel agility feature can identify and switch network operation to the channel with the lowest packet error rate. If the connection between the coordinator and client(s) is broken or the coordinator redundancy deems the bit error rate to be too high, the network will change channels.

Security is also a key in the home network. To avoid unauthorized access, the protocol needs to follow a strict authentication procedure before a connection is granted. Ideally, the network protocol subnet ID should provide reliable security by exercising security on a packet-by-packet basis. WEP encryption algorithm extends the security to each frame transmitted over the air.

For multimedia and quality support, what is needed is a high net throughput for supporting high-fidelity content, such as video transmission. But more than that, efficient bandwidth allocation/usage is needed to support multiple simultaneous content streams (also known as Traffic Category in the IEEE 802.11 Specifications).

To support this traffic in the home, the network must be robust, while at the same time easy-to-use and reliable. Given the unique characteristics of home networking outlined above, this author believes that it is not realistic to expect an enterprise solution to fill the needs of the home network.

? Winter Chan

APAC Vice President

Cirrus Logic





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