standard (1Mbps to 2Mbps) Upgrade of existing IEEE Bit rates of 6Mbps up to 54Mbps Utilises COFDM technology Future WLAN standard

Transcription

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2 ,QWURGXFWLRQ ³:K\,(((D" UL DL AP MT 1 Future WLAN standard Upgrade of existing IEEE standard (1Mbps to 2Mbps) Utilises COFDM technology Bit rates of 6Mbps up to 54Mbps In the 5GHz band DL MT 2 MT 3

3 'HOD\GLYHUVLW\ ³:K\GRZHQHHGLW" MT 5 MT 6 UL DL AP DL UL MT 1 DL MT 2 DL 7UDQVPLWGHOD\GLYHUVLW\ DQHIIHFWLYHPHWKRGWR FRSHZLWKGHJUDGDWLRQV 6LPSOHDQGFRPSOLDQW &RPSHWLWLRQIURPRWKHU KLJKVSHHGZLUHOHVV/$1 VWDQGDUG(76,%5$1 +,3(5/$1 MT 4 MT 3

4 MAC protocol,psohphqwv&60$&$dvedvlvirusurwrfro,qwxuquho\rq,)6wrghwhuplqhdydlodelolw\ri PHGLXP %DFNRIIWLPHVORWVXVHGWRDYRLGFROOLVLRQ Frame MT 1 Frame MT 2 Frame MT 3 DIFS DIFS Frame sensed Elapsed back-off slots Remaining back-off slots Frame Frame Transmission

5 2)'0IUDPHIRUPDW 'HFHQWUDOLVHGZLWKDGLVWULEXWHGDFFHVVVFKHPH 2)'0IUDPHIRUPDWFRQWDLQVSURWRFROVSHFLILFILHOGV $GKRFQDWXUHIUDPHWUDQVPLVVLRQVUHTXLUHQR$3 DOORFDWLRQ HEADER RATE (4 bits) Reserved (1 bit) Length (12 bits) Parity (1 bit) Tail (6 bits) SERVICE (16 bits) PSDU Tail (6 bits) BPSK 1/2 rate Mode that is indicated from RATE PREAMBLE 12 Symbols SIGNAL 1 OFDM symbol DATA Variable number of OFDM symbols Pad bits

6 10 0 3URSRVDO 10-1 PER 10-2 Sent over channel C with average RMS delay spread 150ns Sent over channel A with average RMS delay spread 50ns C/N (db) Fig. 1 shows comparison for transmissions over channel A (50ns RMS delay spread) and C (150ns RMS delay spread) using PHY layer mode 6 3RRUSHUIRUPDQFH UHSRUWHGLQ,((((76, VWDQGDUGFKDQQHO PRGHOµ$ >@ 6XIIHUVIURP LQDGHTXDWH IUHTXHQF\GLYHUVLW\ UHVXOWLQJLQ FRUUHODWHG VXEEDQGV,QWKLVVFHQDULR WKH)(&FRXOGQRW EHH[SORLWHGIXOO\ )LJ GHPRQVWUDWHVWKLV DWWULEXWH

7 3URSRVDO Tk Input data bits Map to constellation OFDM modulation & addcyclic prefix D/A conversion Output to transmitter A Delay, τ d D/A conversion Output to transmitter B Fig. 2a Transmit delay diversity in DL applied to IEEE a standard for the AP )XOO\VWDQGDUGFRPSOLDQW 6\QWKHWLFDOO\HQKDQFHVFKDQQHOE\GHOLEHUDWHO\FUHDWLQJ GHOD\VSUHDGWKXVJHQHUDWLQJDKLJKO\IUHTXHQF\ VHOHFWLYHFKDQQHO )LJDGHPRQVWUDWHVWKHSURSRVHGDQWHQQDDUUD\ FRQILJXUDWLRQDWWKH$3IRUWKH'/PRGH

8 3URSRVDO )LJEGHPRQVWUDWHVWKHSURSRVHGDQWHQQDDUUD\ FRQILJXUDWLRQDWWKH$3IRUWKH8/PRGH Tk Output data bits Map to constellation OFDM modulation & remove cyclic prefix D/A conversion Input from antenna A Delay, τd Input from antenna B Fig. 2b Delay diversity in UL applied to IEEE a standard for the AP

9 5HVXOWV 6RIWZDUHVLPXODWLRQUHVXOWVDUHXVHGWRDQDO\VH SHUIRUPDQFH %DVHGRQVRIW9LWHUELGHFRGLQJ 7UDQVPLWSRZHULVKDOYHGEHWZHHQWKHWUDQVPLW DQWHQQDV Table 1: PHY Layer Modes Mode Modulation Coding Rate Bit rate [Mbps] 1 BPSK 1/2 6 2 BPSK 3/4 9 3 QPSK 1/ QPSK 3/ QAM 1/ QAM 3/ QAM 3/4 54

10 5HVXOWV $OOVLPXODWLRQVDUHEDVHGRQ,((((76,VWDQGDUGFKDQQHO PRGHOV Table 2: IEEE/ETSI channel models Mode Environment Average RMS delay spread (ns) A Office NLOS 50 B Open space/office NLOS 100 C Large open space NLOS 150 D Large open space LOS 140 E Large open space NLOS 250

11 (IIHFWRIGHOD\ 0ns 50ns 100ns 150ns 200ns 250ns 300ns 350ns 400ns Increasing delay between antennas Average RMS delay spread (ns) Fig. 3 RMS delay spreads for transmit delay diversity over IEEE/ETSI channels A /RQJHUGHOD\ODUJHUDYHUDJH506GHOD\VSUHDG *HQHUDWHXQFRUUHODWHGVXEEDQGVWREHH[SORLWHGE\)(&

12 ,PSURYHG3(5SHUIRUPDQFH /RQJHUGHOD\ODUJHUDYHUDJH506GHOD\VSUHDG 7KLVLVUHIOHFWHGE\WKHUHVXOWVLQILJXUH 2YHUFKDQQHO$SHUIRUPDQFH1/26W\SLFDORIILFHHQYLURQPHQW No diversity 0ns 50ns 100ns 150ns 200ns 250ns 300ns 350ns 400ns 3dB gain C/N required for a PER of 10e-2 20 Increasing delay between antennas Fig. 4 PER results of PHY layer mode 6 over various enhanced channels A

13 ,PSURYHG3(5SHUIRUPDQFH $JDLQWKHLPSURYHPHQWVDUHKLJKOLJKWHGDJDLQVWVRIWGHFRGHG RQO\DDQG+,3(5/$13(5SHUIRUPDQFH 35 Soft decoded only a Enhanced a Soft decoded only HIPERLAN/ C/N required for a PER of 10e-2 PHY Layer Modes Fig. 5 PER results of various PHY layer modes over enhanced channel A with a delay of 400ns

14 7KURXJKSXW(QKDQFHPHQW Soft decoded only a Enhanced a Mbit/s 5.2 Mbit/s Throughput (Mbit/s) a Link Throughput a System Throughput Fig. 6 Throughput link enhancements for UL and DL (30m range),qfuhdvhgwkurxjksxwzlwkudqjh

15 'DQJHUVRI,&,,QFKDQQHOVZLWKORQJHUH[FHVVGHOD\ /RVVRIRUWKRJRQDOLW\ No Diversity Fixed 400ns Delay C/N required for a PER of 10e-2 5 A B C D E IEEE/ETSI standard channel models Fig. 7 Comparison of IEEE a performance for various transmit delay diversity strategies in standard channels A, B, C and D using PHY layer mode 6

16 'DQJHUVRI,&, 5DLVHVHUURUIORRU No diversity Diversity with no delay Diversity with delay of 400ns Fig.8 PER performance over channel E using PHY layer mode 6

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