Standards Overview. Joe Bardwell. Connect802 Corporation

Transcription

1 Wireless Data Networking Standards Overview Joe Bardwell President / Chief Scientist joe@.com

2 About Founded in 1994 with headquarters in the San Francisco Bay area and East Coast engineering out of Atlanta, Georgia Providing nationwide Wi-Fi, WiMAX, cellular and other wireless solutions Applying 3-dimensional RF CAD modeling and simulation to the design process Equipment sales, installation and support

3 Wireless Data Networking This presentation will categorize and describe current Wi-Fi, WiMAX and cellular data networking standards and will explain the types of end-user applications and system requirements that are best met by each each. This presentation provides a broad synopsis of the topic and serves as a good review of the individual wireless data networking standards.

4 Wireless Data Networking Wireless, in today s discussion, means the transmission of radio signals Data, in today s discussion, means that information is transmitted as binary 1 s and 0 s Networking means that devices communicate to each other through a structured architecture The structure is typically consistent with one or more underlying organizational schemes: Coverage Cells which define a Layer 1 RF signal propagation zone VLANS ( Virtual LANS ) which define a Layer 2 broadcast domain IP Subnets which define a Layer 3 broadcast domain

5 Network Design A Physical Layer technology is selected to connect each device to its VLAN The switch enforces the VLAN The Data Link from switch to device can include multiple physical layer technologies A packet can be transferred from a wired Ethernet, to a fiber, to a wireless link between a device and the switch (or between switches and routers.) Each Physical Layer is associated with its own Data Link layer You don t get to choose The VLAN and IP architecture is overlaid on the various Data Links to create a cohesive network system The Internet

6 You Must Learn to Balance Your Options I m sorry, but there s no free lunch in the physics department.

7 Capacity The First Question What will the users be doing across the network? Access to local server resources Access to the Internet What are the maximum and minimum bandwidth requirements for each activity? Voice Video Data How many users will simultaneously be hitting the Enter key and then, how long will they be transferring data? Compute the oversubscription ratio Compute the time that the medium will be in use Develop a network design that provides appropriate bandwidth resources to the user community

8 Bandwidth for Voice Voice-over-IP (VoIP) Highly dependent on the CODECs supported by the vendor Requires low latency and jitter in addition to the aggregate capacity Run a PING test to see the general jitter and latency characteristics Latency should not exceed 150 ms Packet loss should not exceed 1% Prioritize VoIP traffic through switches and routers to minimize jitter Codec Information Bandwidth Calculations Codec & Bit Rate (Kbps) Codec Sample Codec Sample Mean Opinion Voice Payload Size Packets Per Second Bandwidth Size (Bytes) Interval (ms) Score (MOS) (Bytes) (PPS) Ethernet (Kbps) G.711 (64 Kbps) 80 Bytes 10 ms Bytes Kbps G.729 (8 Kbps) 10 Bytes 10 ms Bytes Kbps G (6.3 Kbps) 24 Bytes 30 ms Bytes Kbps G (5.3 Kbps) 20 Bytes 30 ms Bytes Kbps G.726 (32 Kbps) 20 Bytes 5 ms Bytes Kbps G.726 (24 Kbps) 15 Bytes 5 ms Bytes Kbps G.728 (16 Kbps) 10 Bytes 5 ms Bytes Kbps

9 Bandwidth for Video User consumption of video bandwidth is dependent on two fundamental specifications of the delivered content What is the pixel resolution of the target display? 704 X 480 (for 16:9 widescreen) 1280 X X 1080 What is the bitrate of the audio codec? Delivering 2 SD and 1 HD video streams with 5:1 audio may require a bandwidth of 15 Mbps Delivering SD video to a standard television set may require as little as 2.7 Mbps Delivering 640 X 480 VGA stereo may require only 350 Kbps per video stream

10 Bandwidth for Data Capture and Calculate Page load = 150,973 bytes = bits Duration = seconds Web Page Download Result = 133 Kbps (Streaming YouTube Video = 377 Kbps) A user with 512 Kbps can do just about anything on the Internet. With 768 Kbps they ll experience generally excellent performance.

11 Choosing Between Technology Options Technology option selection is based on accurately quantifying the requirements Capacity, Throughput, Latency Security, Administration, Regulatory Compliance Interoperability, Support, Integration Capital Expense, Recurring Costs, ROI Project Criticality, Risk Tolerance Technology option selection is constrained by equipment availability and regional carrier deployment schedules and regional carrier deployment schedules You can t choose what s not available!

12 Getting Bandwidth to Your Site Two basic connectivity models: Private Site-to-Site Leased Lines (Frame Relay) MPLS (Multi-Protocol Label Switching) Private IP ATM (Asynchronous Transfer Mode) Internet Connectivity DSL / Cable Modem Leased Copper or Fiber T1 / T3, OC-3, OC-12 Lots of ways to get into the cloud Access Connection How your building connects to the provider s core network Port Connection The provider s connection point to which you attach

13 The Size of the Access Connection DS-1 ( T Mbps) DS-3 ( T3 45 Mbps) OC-3 3( STS STS Mbps) OC-12 (622 Mbps) OC-24 (1.244 Gigabits/sec) OC-48 (2.488 Gigabits/sec) OC-96 (4.976 Gigabits/sec) OC-192 ( 10 Gig SONET Gigabits/sec) OC-255 (9.952 Gigabits/sec) OC-768 (39.8 Gigabits/sec) AT&T MPLS backbone network

14 Getting Bandwidth Between Your Sites Backhaul Connectivity You might have fiber between your buildings or sites Each building may be an edge node in a Private IP or Internet-connected infrastructure VPN tunnels may connect sites through the Internet You might use point-to-point or point-to-multipoint radio equipment to configure a series of links between nodes to implement a topology that you have designed. This is called a Wireless Distribution System (WDS) or, simply, Transparent Bridging You might use radio equipment that automatically discovers neighbor radios, computes the best-path through to the destination, and automatically establishes point-to-point links between nodes. This is called a Mesh Network and the nodes are often called Mesh Routers WDS and Mesh Backhaul Often Supports Client Access Wi-Fi, Video Surveillance or Video Signage

15 Essential Wireless Engineering The various standards define both the PHY and the MAC layers PHY specifies modulation and coding MAC specifies access control rules and error response Data bits are represented by specified changes (modulation) in the transmitted electromagnetic signal The phase, amplitude or frequency can be changed Groups of changes represent groups of bits i.e. two different phases with two different amplitudes = 4 combinations which could represent four different possible bit combinations: 00, 01, 10, 11 As the modulation and bit representation scheme becomes more elaborate it becomes more prone to corruption by noise or interference More sophisticated ( expensive ) radio equipment is required to support a more elaborate modulation and bit representation scheme

16 Getting Bandwidth to Your Users The Cellular Network Public Mobile WiMAX Sprint in Baltimore Private Fixed WiMAX Private Mobile WiMAX Not yet Wi-Fi Proprietary Gigabit Radios There are many choices and decisions to be made

17 Evolution Data Optimized (EVDO) Verizon uses EVDO with CDMA to compete with AT&T Sprint also uses EVDO Speeds between 300 Kbps and 512 Kbps up to 2 Mbps near towers and with good SNR Commercially available in over 180 U.S. metropolitan areas

18 High-Speed Downlink Packet Access (HSDPA) AT&T uses HSDPA with GSM to compete with Verizon Singular s Broadband Connect network is HSDPA Speeds between 400 Kbps and 700 Kbps with bursts up to 1 Mbps A subcategory of Universal Mobile Telecommunications Systems (UMTS) which h includes GSM QPSK and 16-QAM between 1.2 Mbps and 42.2 Mbps 3GPP (3 rd Generation Partnership Project) Phase 1 introduction targets data rates of 14 Mbps Commercially in over 165 major U.S. cities and over 120 countries

19 Cellular Repeater Design

20 WiMAX Connectivity d Fixed WiMAX 75 Mbps per 20 MHz channel using 64-QAM (3/4 coding rate) In the real world the maximum may upwards of 30 Mbps {These are TCP/IP data rates, not modulation rates } e Mobile WiMAX Sprint intends to deliver 2 Mbps to 4 Mbps using e There is testing being conducted with OFDM 4 X 2 MIMO systems that promise throughput over 35 Mbps for mobile users Currently these tests are predicting up to 10% outage probability WiMAX uses variable sub-carrier counts in OFDM to maximize efficiency in the presence of noise or interference Wi-Fi simply pydrops back to the next lower rate The WiMAX drop back is a smaller, more granular step

21 WiMAX Standards and Considerations (10 to 16 GHz range) a (2004, 2 to 11 GHz range) d (2005, OFDM with 256 sub-carriers 200 used) e (2005, Scalable OFDM Access and full mobility support) The number of carriers varies with the SNR The Wi-Fi Problem that WiMAX Fixes Wi-Fi clients wait for a clear channel then transmit This is a random process Stations close to an access point have better performance than those that are further away Clients associate to the best access point but then hang on until their connectivity it drops to the minimum i levell WiMAX utilizes a scheduling algorithm that uses variable size time slots that allow the medium contention process to more efficiently utilize wireless bandwidth The MAC layer is Connection-Oriented

22 Mobile Broadband Wireless Access (MBWA) IEEE Working Group established 2002 Standards approved June 2008 Peak data rates per user in excess of 1 Mbps Vehicular mobility up to 250 Km/h Number of active users to be significantly higher than other standards Comparing to e.16e operates in 2 to 6 GHz bands while.20 operates only in licensed spectrum below 3.5 GHz.16e targets mobile users with PDAs, laptops and phones while.20 focuses on vehicle mobility This makes.20 more of a competitor to cellular than to.16e

23 Wireless Regional Area Network (WRAN) Uses white space in the TV frequency spectrum Shares geographically g unused spectrum using cognitive radio techniques has the potential to provide coverage cells of up to 20 miles OFDM with 16-QAM and 64-QAM with variable coding rates Necessary to dynamically adapt to each unique environment Anticipated channel capacity is 18 Mbps Supports individual user connections of 1.5 Mbps down / 384 Kbps up

24 Wi-Fi Standards and Options

25 Wi-Fi Standards Wi-Fi: The Wireless Fidelity Alliance June GHz 1 and 2 Mbps w/50% Throughput a September GHz 6 to 54 Mbps w/50% Throughput b September GHz 1 to 11 Mbps w/50% Throughput h c 2001 Bridge operation (ultimately included in d) d 2001 International roaming extensions to differentiate regulatory domains e 2001 Quality of Service enhancements to support VoIP f Load balancing between multiple vendors access points (Withdrawn)

26 Wi-Fi Standards g June GHz 6 to 54 Mbps w/50% Throughput h 2004 Spectrum management for European compatibility i 2004 Security enhancements including WPA and WPA j 2004 Enhancements for the Japanese market k 2008 Radio resource measurement and monitoring enhancements l Typographically Unsound n March 2007 Draft 2 Up to 300 Mbps w/75% Throughput 24GHzand58GHz y November 2008 Licensed 3.7 GHz up to 20 W 6 to 54 Mbps w/50% Throughput ad High throughput in the 60 GHz frequency band (2012?)

27 Wi-Fi Standards and Options b/g 2.4 GHz ISM Band Lots of noise and interference b data rates of 1, 2, 5.5 and 11 Mbps use BPSK and QPSK modulation which is reasonably noise tolerant g uses OFDM modulation which can be extremely noise sensitive at higher data rates Maximum 54 Mbps modulation yields 22 Mbps TCP/IP throughput You get roughly ½ the modulation rate for data transport A 10 Mbps average aggregate capacity is more realistic Throughput and connectivity can be predicted through the use of RF CAD simulation software a It s g (OFDM) in the 5.8 GHz band

28 Why Does n Have Greater Capacity? Modified OFDM Subcarriers increased from 48 to 52 This increases connection rate from 54 Mbps to Mbps Forward Error Correction (FEC) Sender adds redundant data to allow receiver to detect and correct errors a/g 3/4 coding rate is increased to 5/6 This increases connection rate from Mbps to 65 Mbps Shorter Guard Interval (GI) OFDM inter-symbol guard interval reduced from 800ns to 400ns This increases connection rate from 65 Mbps to Mbps

29 Why Does n Have Greater Capacity? Channel Bonding Channel bandwidth is increased from 20 MHz to 40 MHz This increases connection rate from 72.2 Mbps to 150 Mbps Better than twice because there is no guard band between adjacent channel space Spatial Multiplexing Support for up to four spatial streams (MIMO) This increases bandwidth up to four times Approximately 150 Mbps, 300 Mbps, 450 Mbps, 600 Mbps

30 MCS 0 31 Define Connectivity Up to 600 Mbps MCS Provide Legacy 48 Sub-Carrier OFDM And Are Unused

31 MCS 0 31 Define Connectivity Up to 600 Mbps MCS Provide Legacy 48 Sub-Carrier OFDM And Are Unused

32 802.11a/b/g versus n For a/b/g: Assume 50% throughput 54 Mbps modulation yields 22 Mbps TCP/IP throughput 54 Mbps will be available only with direct LOS and up to roughly 50 feet For n: Assume 75% throughput A 65 Mbps connection yields 48 Mbps TCP/IP throughput 65 Mbps will be available only with direct LOS and up to roughly 50 feet To get above 65 Mbps will require either 40 MHz channels, a second spatial stream with MIMO, or both (for 230 Mbps yielding 172 Mbps TCP/IP connectivity) a/b/g is 1/3 to 1/2 less expensive than n

33 Wireless Personal Area Networks (WPAN) IEEE (Bluetooth) provides 11 to 55 Mbps Task Group 3 (TG3) developing millimeter-wave WPAN for > 2 Gbps access 16 Channels, 5 MHz Wide (ZigBee) provides 250 kbps but very in the 2.4 GHz Band low complexity, power and cost Operates in MHz and GHz QPSK up to 250 kbps in a mesh topology TG6 BAN (Body Area Network) short-range range mesh TG7 VLC (Visible Light Communications) WirelessHART Proprietary instrumentation i process control Consistent with SCADA Supervisory Control And Data Acquisition

34 And let s not forget DECT (Digital Enhanced Cordless Telecommunications) Originally 1880 MHz to 1900 MHz developed in Europe Uses Frequency Shift Keying (FSK) for voice Can use QPSK for up to 2 Mbps data rates FCC 2005 rule changes allowed operation in the Unlicensed Personal Communications Services (UPCS) band at 1.9 GHz DECT 6.0 EDGE (Enhanced Data Rates for GSM Evolution) 400 Kbps with peak up to 1 Mbps Up to 8-PSK (8 phase rotation angles with a single sine wave) AT&T Mobility, Cincinnati Bell, Mid-Tex Cellular and others)

35 And let s not forget 802.1ag / Y1731 Service Layer OAM Standards to facilitate the discovery and path verification through bridge devices Facilitate VLAN implementation in a bridged architecture Define management protocols and methodologies RFC 2544 Standardized Network Testing Seeks to provide a common basis for comparing and contrasting performance between different networks or different network equipment implementations Presents standard test methodology and test suites Throughput under bursty traffic conditions Overall capacity, throughput and latency Frame loss rate Routing performance when path changes occur: RIP, OSPF, IGRP

36 You Need to Quiz Your Service Providers!

37 A Real-World Example 2,700 Feet T3 upgradable to OC-3 at the Telco demarc

38 A Real-World Example Proprietary 80/20 (100 Mbps) Link to Central Tower

39 A Real-World Example 45 Mbps WiMAX cloud to interconnect building groups

40 A Real-World Example a Backhaul (20 Mbps TCP/IP) to interconnect buildings in each group

41 A Real-World Example Dual-Radio a / b/g for connectivity into residences

42 A Real-World Example Outdoor Wi-Fi, backhaulconnected to the WiMAX cloud via a and with 900 MHz Point-to-to Point through trees

43 A Real-World Example In-Building Wi-Fi and Cellular Repeaters

44 Thoughts to Take Away You can have a privately-owned system that can push a 100 Mbps data stream over a 120 mile range You just need really tall towers and a non-trivial budget Gigabit wireless is a commercially viable option that t may be ideally suited and very cost-effective for inter-building or inter-site links of less than 5 miles. You can often take advantage of lite licensed frequencies to avoid noise and interference There s no free lunch in the physics department You ll always be making trade-offs between throughput, h t range, cost and other factors Today s standards make it possible to have high-capacity wireless and remote-site networks implemented with relative ease Again, there are proportionate up-front and recurring costs to consider An optimal network design may often integrate various standards, each providing the most efficient solution to a particular element of the design.