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Figure 3: SWAP frame description

Figure 3 SWAP frame description

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The networking vision of the HomeRF WG is shown in Figure . The RF technology supports both a network of isochronous clients that are slaves to the main home PC, and a network of asynchronous peer devices that is effectively a wireless Ethernet. n most cases the system contains a Connection Point (CP), which is usually connected to the main home PC via USB. The isochronous clients such as cordless telephones, wireless headsets, or remote I/O devices to the home PC (a consumer Personal Information Manager or PIM) are always bound to the CP which assigns them guaranteed bandwidth for bounded atency communication. For asynchronous communications between devices the CP is not absolutely necessary. Asynchronous peer devices can communicate with each other directly and the main home PC is just another peer device. Figure 1: HomeRF WG’s vision for Home Networking
The networking vision of the HomeRF WG is shown in Figure . The RF technology supports both a network of isochronous clients that are slaves to the main home PC, and a network of asynchronous peer devices that is effectively a wireless Ethernet. n most cases the system contains a Connection Point (CP), which is usually connected to the main home PC via USB. The isochronous clients such as cordless telephones, wireless headsets, or remote I/O devices to the home PC (a consumer Personal Information Manager or PIM) are always bound to the CP which assigns them guaranteed bandwidth for bounded atency communication. For asynchronous communications between devices the CP is not absolutely necessary. Asynchronous peer devices can communicate with each other directly and the main home PC is just another peer device. Figure 1: HomeRF WG’s vision for Home Networking
Table 1: Translation of key requirements emerging from market survey to design decisions
Table 1: Translation of key requirements emerging from market survey to design decisions
Figure 2: SWAP-CA network topology flexibility configuration the network is under the explicit control of a CP, which functions as its gateway to other devices, the Internet, and the PSTN. Furthermore, in this mode the network can simultaneously support both real-time audio traffic, such as interactive voice, and non-real time data traffic such as traditional TCP connections. In the ad-hoc network mode the network provides traditional data networking support only and does not need a CP for proper operation. It is possible for two or more SWAP-CA networks to co- exist at the same time even when they are within range of one another. This is explained in the following sub-section.
Figure 2: SWAP-CA network topology flexibility configuration the network is under the explicit control of a CP, which functions as its gateway to other devices, the Internet, and the PSTN. Furthermore, in this mode the network can simultaneously support both real-time audio traffic, such as interactive voice, and non-real time data traffic such as traditional TCP connections. In the ad-hoc network mode the network provides traditional data networking support only and does not need a CP for proper operation. It is possible for two or more SWAP-CA networks to co- exist at the same time even when they are within range of one another. This is explained in the following sub-section.
Table 3: Typical values of some attributes used by the MAC layer OO - Typical values for parameters used by the MAC are shown in Table 3.
Table 3: Typical values of some attributes used by the MAC layer OO - Typical values for parameters used by the MAC are shown in Table 3.
Sender selects a slot (backoff counter) and then decrements the counter whilst the medium is clear «Medium must be free for a DIFS period before the backoff counter is decremented. «Example shows transmission of a packet in slot 5. The CSMA/CA protocol attempts to avoid collision by adopting listen-before-transmit LBT) etiquette -- sensing transmissions on the radio medium and starting transmission when there is no such activity. The mechanism is similar to Ethernet IEEE 802.3 [4]]), enabling easy integration with an existing TCP/IP protocol [19] stack within a host difference with Ethernet is the platform; the main slotted contention mechanism and the addition of MAC level ACK of unicast packets. Figure 4 illustrates accessed during the contention period. how the medium is
Sender selects a slot (backoff counter) and then decrements the counter whilst the medium is clear «Medium must be free for a DIFS period before the backoff counter is decremented. «Example shows transmission of a packet in slot 5. The CSMA/CA protocol attempts to avoid collision by adopting listen-before-transmit LBT) etiquette -- sensing transmissions on the radio medium and starting transmission when there is no such activity. The mechanism is similar to Ethernet IEEE 802.3 [4]]), enabling easy integration with an existing TCP/IP protocol [19] stack within a host difference with Ethernet is the platform; the main slotted contention mechanism and the addition of MAC level ACK of unicast packets. Figure 4 illustrates accessed during the contention period. how the medium is
Figure 6: Power management of TDMA nodes in a SWAP-CA network
Figure 6: Power management of TDMA nodes in a SWAP-CA network
Figure 8: Power management of CSMA nodes for unicast messages
Figure 8: Power management of CSMA nodes for unicast messages
Figure 7; Power management of CSMA nodes for broadcast messages
Figure 7; Power management of CSMA nodes for broadcast messages
ne In fact, ‘the entire SWAP-CA PHY- -layer specification has been written specifically to accommodate very low cost, single-chip implementation in CMOS technology. A typical system partitioning is shown in Figure 9. For many of the digital devices envisioned by the HomeRF WG, the digital MAC baseband portion of the component solution can be integrated into a large Application Specific Integrated Circuit (ASIC) already in the device. At ~30K gates for the SWAP-CA data core, this is extremely low cost in the sub-0.25 um CMOS era. The modem functionality can interface to the digital baseband via a very simple serial interface (with no analog quantities). The modem and RF functionality can all be integrated into a single mixed-signal CMOS Integrated Circuit (IC) as shown because of the specific technica requirements on filtering and modulation chosen by the HomeRF technical team. Note that it probably does not make sense to integrate the RF front-end functionality such as the low-noise amplifier, the power amplifier (if present), the antenna switches and the band-select filter onto the CMOS IC even though technically feasible. This is because the semiconductor die area for the front-end functions is typically much less than 5% of the rest of the modem (hence low cost already) and the overall power consumption performance is driven largely by optimizing these functions in detail. Figure 9: Partitioning of RF Modem and Digital MAC Component Sections
ne In fact, ‘the entire SWAP-CA PHY- -layer specification has been written specifically to accommodate very low cost, single-chip implementation in CMOS technology. A typical system partitioning is shown in Figure 9. For many of the digital devices envisioned by the HomeRF WG, the digital MAC baseband portion of the component solution can be integrated into a large Application Specific Integrated Circuit (ASIC) already in the device. At ~30K gates for the SWAP-CA data core, this is extremely low cost in the sub-0.25 um CMOS era. The modem functionality can interface to the digital baseband via a very simple serial interface (with no analog quantities). The modem and RF functionality can all be integrated into a single mixed-signal CMOS Integrated Circuit (IC) as shown because of the specific technica requirements on filtering and modulation chosen by the HomeRF technical team. Note that it probably does not make sense to integrate the RF front-end functionality such as the low-noise amplifier, the power amplifier (if present), the antenna switches and the band-select filter onto the CMOS IC even though technically feasible. This is because the semiconductor die area for the front-end functions is typically much less than 5% of the rest of the modem (hence low cost already) and the overall power consumption performance is driven largely by optimizing these functions in detail. Figure 9: Partitioning of RF Modem and Digital MAC Component Sections
Table 4: Typical values of some attributes used by the PHY layer eak\aaieape es a ‘- ws With such high levels of integration and optimized front-end, the RF modem section overall cost in multi- million unit volume should be well below $10 (similar to the situation today with DECT equipment) while the digital MAC section approaches “zero” other than IP royalties. Note that while this seems extraordinarily low compared to today’s common perception of RF data being $100’s per node, it is still very expensive compared to the very low cost of IrDA transceivers or USB controllers. Thus cost remains a significant issue to making HomeRF a “throwaway” item in every electronic device. But consumers have consistently shown with voice that they will pay extra for personal mobility. Even today, cordless phones are significantly more expensive than corded phones yet much more popular. If consumers begin to value mobility within the home for Internet- based content the way they do today for PSTN-based content, then the present cost projections for enabling SWAP-CA in devices should not be a serious barrier. Table 4 contains some typical values used by the SWAP- CA PHY layer.
Table 4: Typical values of some attributes used by the PHY layer eak\aaieape es a ‘- ws With such high levels of integration and optimized front-end, the RF modem section overall cost in multi- million unit volume should be well below $10 (similar to the situation today with DECT equipment) while the digital MAC section approaches “zero” other than IP royalties. Note that while this seems extraordinarily low compared to today’s common perception of RF data being $100’s per node, it is still very expensive compared to the very low cost of IrDA transceivers or USB controllers. Thus cost remains a significant issue to making HomeRF a “throwaway” item in every electronic device. But consumers have consistently shown with voice that they will pay extra for personal mobility. Even today, cordless phones are significantly more expensive than corded phones yet much more popular. If consumers begin to value mobility within the home for Internet- based content the way they do today for PSTN-based content, then the present cost projections for enabling SWAP-CA in devices should not be a serious barrier. Table 4 contains some typical values used by the SWAP- CA PHY layer.
Figure 10: Interfaces exposed by a SWAP-CA device. Due to the wide scale availability of the Microsoft's Windows operating system and its use as a de-facto standard operating system for home PCs, the HomeRF WG sought to streamline operation of SWAP-CA devices on these systems. We now briefly describe how SWAP- CA devices operate in the context of a main-line operating system.
Figure 10: Interfaces exposed by a SWAP-CA device. Due to the wide scale availability of the Microsoft's Windows operating system and its use as a de-facto standard operating system for home PCs, the HomeRF WG sought to streamline operation of SWAP-CA devices on these systems. We now briefly describe how SWAP- CA devices operate in the context of a main-line operating system.
- Windows defines a Network Device Interface Specification (NDIS) [24] for programming networking hardware. The implementation of networking hardw mapping, interru the functions that DIS software library, which is the this specification, performs many of are common to device drivers of are including synchronization, device pt handling, event logging, etc. Furthermore, it provides a standard interface for higher- evel protocols and adapters write a given media type knowledgeable ab software modules hardware vendor applications, which can be agnostic of the underlying hardware. Manufacturers of network NDIS miniport driver that provides functionality specific to their hardware. Miniports of a can be used by higher-level protocols out that media type with no further modifications. Figure 11 illustrates how the various fit together. The shaded blocks are provided as standard part of the operating system and the writes the miniport device drivers. Miniport drivers that are written to conform to the NDIS specification are guaranteed to work with the Windows operating system.
- Windows defines a Network Device Interface Specification (NDIS) [24] for programming networking hardware. The implementation of networking hardw mapping, interru the functions that DIS software library, which is the this specification, performs many of are common to device drivers of are including synchronization, device pt handling, event logging, etc. Furthermore, it provides a standard interface for higher- evel protocols and adapters write a given media type knowledgeable ab software modules hardware vendor applications, which can be agnostic of the underlying hardware. Manufacturers of network NDIS miniport driver that provides functionality specific to their hardware. Miniports of a can be used by higher-level protocols out that media type with no further modifications. Figure 11 illustrates how the various fit together. The shaded blocks are provided as standard part of the operating system and the writes the miniport device drivers. Miniport drivers that are written to conform to the NDIS specification are guaranteed to work with the Windows operating system.
Figure 12: SWAP-CA for isochronous service driver architecture
Figure 12: SWAP-CA for isochronous service driver architecture
Table 5: Comparison of SWAP-CA with other connectivity options
Table 5: Comparison of SWAP-CA with other connectivity options
Related topics:
Biomedical EngineeringPower ManagementAd hoc networkWireless LanWireless accessTelecommunication networkHome NetworkElectrical and Electronic EngineeringPublic Switched Telephone Network
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