1. doc.: IEEE 802.11-02/220r0 Submission March 2002 A. Batra et al., Texas InstrumentsSlide 1 Proposal for a 4 Channel Option to Increase Capacity in the 2.4 GHz ISM Band Anuj Batra Kofi Anim-Appiah Matthew B. Shoemake Texas Instruments March 12, 2002

2. doc.: IEEE 802.11-02/220r0 Submission March 2002 A. Batra et al., Texas InstrumentsSlide 2 Motivation (1) To use the spectrum in the 2.4 GHz ISM band more efficiently. To increase the number of simultaneous users that can be supported in a given network. To make network planning in enterprise environments easier. Even though the primary focus for IEEE 802.11g has been on data rate extensions, capacity extensions are just as important. Should consider methods for increasing capacity that will prolong the utility of the IEEE 802.11g standard.

3. doc.: IEEE 802.11-02/220r0 Submission March 2002 A. Batra et al., Texas InstrumentsSlide 3 Motivation (2) IEEE 802.11b standard currently allows for only three non-overlapping channels: –Channels 1, 6, and 11 (channel spacing = 25 MHz). IEEE 802.11a standard uses a channel spacing of 20 MHz. Total available spectrum = 83.5 MHz. Could we use a channel spacing of 20 MHz for the IEEE 802.11g standard? If we could reduce the channel spacing, then it would be possible to place four non-overlapping channels in the ISM band.

4. doc.: IEEE 802.11-02/220r0 Submission March 2002 A. Batra et al., Texas InstrumentsSlide 4 Implications / Constraints Reducing the channel spacing to 20 MHz: –Primarily affects single-carrier signals: Barker, CCK, and PBCC, in the IEEE 802.11g draft. –Need to verify that we can restrict the bandwidth of the single-carrier signals to 20 MHz. –Should not have an impact on the multi-carrier signals in the IEEE 802.11g draft, because those signals were designed to work with a channel spacing of 20 MHz. Need to verify that it is still possible to transmit at least 20 dBm on each channel when the channel spacing is reduced. The exact transmit power levels will depend on factors such as: –Spectral regrowth introduced by the PA. –Noise from DAC. –EVM of the transmitted signal.

5. doc.: IEEE 802.11-02/220r0 Submission March 2002 A. Batra et al., Texas InstrumentsSlide 5 By using spectral shaping, it is possible to restrict the bandwidth of a single-carrier signal to 20 MHz. –Ex: SR-RC filter ( = 0.6) that extends over 4 symbols (before PA). –99.994% of the energy is contained within 20 MHz of f c (42-db BW = 20 MHz). Spectral Shaping for Single-Carrier Signals

6. doc.: IEEE 802.11-02/220r0 Submission March 2002 A. Batra et al., Texas InstrumentsSlide 6 FCC Regulations Need to ensure that new channelization scheme meets FCC out-of-band requirements (15.205 and 15.209). Restricted bands of operation (15.205): –2310 MHz – 2390 MHz (band below the ISM band). –2483.5 MHz – 2500 MHz (band above the ISM band). For frequencies in the restricted bands above 960 MHz, the emissions from an intentional radiator shall not exceed a field strength of 500 V/m when measured at a distance of 3m (15.209). –Equivalent to an average radiated power of –41.25 dBmi in any 1 MHz band. –The transmission duty cycle within a 100msec period must also be considered when measuring the average radiated power.

7. doc.: IEEE 802.11-02/220r0 Submission March 2002 A. Batra et al., Texas InstrumentsSlide 7 Proposed 4 Channel Option Define CHNL_ID = 0 to correspond to a center frequency of 2407 MHz. Propose the following optional 4 channel scheme for the IEEE 802.11g draft. –Channel spacing = 20 MHz. –Channels 0 and 12 are approximately the same distance from the forbidden bands.

8. doc.: IEEE 802.11-02/220r0 Submission March 2002 A. Batra et al., Texas InstrumentsSlide 8 Total transmit power for each channel is 20 dBm (Resolution BW = 1 MHz). SR-RC transmit filter ( = 0.6) that spans 4 symbols. Rapp Model with p = 3. Spectrum for Single-Carrier Modulation

9. doc.: IEEE 802.11-02/220r0 Submission March 2002 A. Batra et al., Texas InstrumentsSlide 9 Spectrum for Multi-Carrier Modulation Total transmit power for each channel is 20 dBm (Resolution BW = 1 MHz). Tapering transition duration of T TR = 150 ns. Rapp Model with p = 3.

10. doc.: IEEE 802.11-02/220r0 Submission March 2002 A. Batra et al., Texas InstrumentsSlide 10 Conclusion Proposed a new optional channelization scheme for the IEEE 802.11g standard that accommodates 4 non-overlapping channels. Showed that it may be possible to transmit at least 20 dBm on each of the 4 channels and still meet FCC requirements. –Further study is needed.