HomeRF Overview and Market Positioning
4 HomeRF Technical Specification
The SWAP system can operate either
as an ad-hoc peer to peer network that provides traditional data
networking or as a managed network under the control of a connection
point. A SWAP network can consist of three types of devices.
- Control Point
- Isochronous voice devices
- Asynchronous data devices
Using a contention-based protocol the connection point
can perform data transfers to and from other data devices. The SWAP
protocol is a client server between the control point and the voice
devices but is peer to peer between the control point and data devices.
HomeRF uses, references and maps existing network
layers. However, HomeRF has modified the existing technologies for the
Physical (PHY) and Data Link (MAC) layers. Figure 4.1 illustrates the
network layers of HomeRF.
Figure 4.1: Network layers of HomeRF
4.1 MAC Layer
MAC is optimized for the home environment and is
designed to carry both voice and data traffic and to inter-operate with
the PSTN using a subset of DECT. A TDMA service is used to support the
delivery of Isochronous data and a CSMA/CA service (derived from Wireless
LAN standard IEEE802.11) is provided to support the delivery of
asynchronous data. This can be seen more clearly in figure 4.2.
Figure 4.2: SWAP Origin
The SWAP MAC provides the following features:
- Good support for voice and data by using both TDMA and CSMA/CA
access mechanisms.
- Support for 4 high quality voice connections.
- High data throughput 1.6Mbps.
- Data security.
- Power management for Isochronous and Asynchronous nodes.
- 24 bit Network ID.
4.2 PHY Layer
The PHY specification for SWAP was
largely adopted from IEEE802.11FH. It has been modified significantly to
reduce cost, allow a single chip implementation while still maintaining
more than adequate performance for home usage scenarios. Some key SWAP PHY
layer specifications include:
- Transmit power up to +24dBm
- Receiver Sensitivity in 2FSK
- Optional low power transmit mode: 0 to 4 dBm for portable devices.
Introduction | Working
Group | Vision | Technical Specification | Software
Architecture |
Security | Implementations | Rival
Technologies | Future
|
