Gigabit Ethernet UTP-5 PHY ¥ Contacts: Ð Barry Hagglund Manager Product Research (presenting) Ð Vernon Little Manager LAN Marketing Ð Brian Gerson Manager Analog Development Ð Steve Dabecki Senior Designer, Gigabit PHY PMC-Sierra, Inc. 105-8555 Baxter Place Burnaby, B.C. Canada V5A 4V7 tel: 604.415.6000 ----------------- Proposed Gigabit Ethernet PHY ¥ Gigabit Ethernet PHY interface; Ð 50 m short-haul - Full Duplex UTP-5, 4-pair interface È one device, roadmap to 100 m Ð 100 m intermediate - Full Duplex UTP-5, 8-pair interface È two devices plus GMII mux logic, roadmap to 200 m ¥ Basic Elements: Ð Gigabit MII between MAC and PHY (G-MII - ÔjimmyÕ) Ð Pair division multiplexing Ð 4 Level Line encoding Ð Zero state frame delineation (4LZS) Ð Data Scrambling for spectrum management Ð Clock and data recovery Ð Bit and word synchronization ¥ Continuous time analog, based on existing technology ----------------- 4 Pair vs. 8 Pair 4-Level Code ¥ When coding n bits per pulse, for a bit rate of B, the pulse (symbol) rate is B/n ¥ 4 Level gives 2 bits per symbol Ð 500 Mbits transmits in 250 Mbaud ¥ One dimensional code - one degree of complexity ----------------- Quaternary Slicer SNR ¥ Intrinsic coding power density at slicer is the symbol variance ¥ SNR = s2s / s2n ; ÆSNR = s2s2B1Q / s2sNRZ ¥ s2s = 1/Lc·i ¥ s2s2B1Q = 1/4{(-3)2+(-1)2+(1)2+(3)2} = 5 ¥ s2sNRZ = 1/2{(-1)2+(1)2} = 1 ¥ ÆSNR = s2s2B1Q / s2sNRZ= 10 log(5/1) = 7 dB ----------------- Relative Noise Immunity ¥ Flat channel noise power is proportional to the symbol rate [1/T] Ð Æsnflat = - 10 log [T2B1Q/TNRZ] = 2 dB @ 250 Mbaud vs. 155 Mbit NRZ ¥ Self-NEXT noise power is proportional to the cubed square root of the symbol rate [T]3/2 Ð Æsnsnext = - 15 log [T2B1Q/TNRZ] = 3 dB @ 250 Mbaud vs. 155 Mbit NRZ ¥ Pair-pair NEXT noise power is frequency and cable geometry dependent Ð N(Ä) = c Ä 3/2 G(Ä) ; c = 6.31 x 10-7 for Category 5 = 3 dB @ 250 Mbaud 2B1Q vs. 155 Mbit NRZ ----------------- PHY Comparisons Modelled Eye Diagram: 20m UTP-5 Modelled Eye Diagram: 20m & Magnetics ¥ Significant difference in eye opening ¥ Modelled with 266 F/C magnetics ¥ Lab work with Pulse PE65508 shows promise ----------------- Experimental Eye Diagram: 20m UTP-5 Experimental Eye Diagram: 26m UTP-5 ----------------- Spectrum Management ¥ For a similar launch level 4LZS engery is spread over a wider area Hence, lower energy at individual spectral lines ¥ Use of a scrambler spreads the energy across the spectrum, reducing the energy for radiation at a spectral line. ----------------- Frame Handling ¥ Bytes from GMII word byte mutliplexed on different pairs ¥ IDLE pattern maintains bit and word synch ¥ IDLE to PREAMBLE code delimits start of frame ¥ Zero State signalling delimits end of frame Ð EOF turns off transmitter for one byte (4 quats) Ð Receiver requires quiescent detection comparators and digital decoding ¥ IDLE codes could be used to indicate ESCAPEÕs Ð eg. IDLE defined over 3 quats with 4th used for codes ¥ IPG used for IDLE codes and Zero State Ð minimum IPG > 96 bits = 12 bytes Ð in 8 pair system - 3 bytes per Tx pair - 1 ZS & 2 IPG Bytes ----------------- Gigabit Media Independent Interface (G-MII) ¥ Generalize 802.3u MII for Fast Ethernet ¥ 8-bit wide data, clocked at 125 MHz Ð TX_ER RX_ER CRS TX_EN RX_DV COL TX_CLK RX_CLK MDC TXD[7:0] RXD[7:0] MDIO TX_CLKR Ð 26 pins total Ð ÔFlow through timingÕ - Clocks transmitted with data ¥ 16 bit data also considered Ð 44 pins total Ð Octet Identification required ----------------- G-MII Timing ¥ 8-bit Timing (Odd number of bytes) ¥ PHY transmitter sources clock; clock flows back with data to PHY ----------------- Gigabit PHY Block Diagram ----------------- Ongoing Work ¥ BER performance over temperature ¥ Confirm spectral and FCC results ¥ ÔESCAPEÕ words required Ð Error conditions, TSC ? ¥ DC balance requirements Ð Decision feedback at receiver vs. transmitter RDS correction ¥ Transmit templates and slicing levels ----------------- ----------------- Supplementary Material ----------------- RJ-45 Pin Assignment (DTE) 4LZS Code Assignment ¥ QPSK & ISDN proven grey code assignment ¥ Equal Hamming distance between symbols Ð Electrical Levels subject to verification ----------------- Reach Calculations EIA/TIA-568 Specs for UTP ¥ Characterized to 100 MHz ¥ NEXT and Loss limited in length and frequency ¥ Empirical results show headroom ----------------- Cable Model Match to 568 Received Data - 155 Mbit/s Equalized Receiver - 155 Mbit/s ----------------- FCC Radiated Emission Limits ¥ Radiated Emission Limits FCC Ambient Environment ¥ Horizontal Antennae FCC Ambient Environment ¥ Vertical Antennae Workstation Radiated ¥ Horizontal Antennae Workstation Radiated ¥ Vertical Antennae 155-UTP Radiated ¥ Horizontal Antenna 155-UTP Radiated ¥ Vertical Antennae