applied wireless electronics grzegorz budzy „ lecture 7

AppliedApplied WirelessWireless ElectronicsElectronics

Grzegorz BudzyGrzegorz Budzyńń

LLectureecture 77::Wireless data transfer Wireless data transfer –– GSMGSM

Plan

• WiFi - supplement

• GSM 2.5G+ standards

– HSCSD

– GPRS

– EDGE

– UMTS

– HSDPA

– HSUPA

– LTE

WiFi - Supplement

WiFi – new standards

• The old standards cover 80-90 % of thebandwidth demand of today’s mobile applications

• New standards enter the market:– 802.11ac

– 802.11ad

WiFi – 802.11ac• Major features:

– Wider channels:• Higher data rates – up to 1.3Gbps per radio

• 802.11ac mandates support of 80MHz wide channels with optional 160MHz wide channels to achieve higher data rates than are achieved with 802.11n


– Wider channels:• Main disadvantage – smaller number of available

channels


– Higher encoding density:• Higher bit density per packet• 256-QAM modulation used

– Increased number of spatial streams:• Higher data rates per AP/client link

• Up to eight spatial streams, further increasing the data rate for each radio


– Beamforming:• Greater wireless AP/client link reliability

– Multi-user MIMO• Greater AP/client capacity and efficient use of spectrum

• Supports simultaneous transmissions to multiple clients and maximizes RF band utilization

• Up to four distinct clients can receive data simultaneously from a single AP at full channel data rate

WiFi – 802.11ac

• Timetable for commercial availability

WiFi – 802.11ad

• IEEE 802.11ad is an amendment to the 802.11 WLAN standard which enables up to 7 Gbps data rates in the unlicensed and globally available 60 GHz band

• The 60 GHz band has wider channels, enabling higher data rates over short distances (1m – 10m)

WiFi – 802.11ad

• Main applications:– Removing wires between High-Definition

multimedia, computer displays, I/O and peripheral,

– peer to peer data synchronization

– higher speed LAN

WiFi – 802.11ad

• A shared MAC layer with existing 802.11 networks enables session switching between 802.11 networks operating in the 2.4 GHz, 5 GHz and 60 GHz bands

• The 802.11ad MAC layer has been extended:– to include beamforming support

– address the 60 GHz specific aspects of channel access, synchronization, association, and authentication

GSM - Introduction

Cellular Network• Base stations transmit to and receive from mobiles at the

assigned spectrum

– Multiple base stations use the same spectrum (spectral reuse)

• The service area of each base station is called a cell

• Each mobile terminal is typically served by the ‘closest’ base

stations

– Handoff when terminals move

Cellular Network Generations• It is useful to think of cellular Network/telephony in

terms of generations:

– 0G: Briefcase-size mobile radio telephones

– 1G: Analog cellular telephony

– 2G: Digital cellular telephony

– 3G: High-speed digital cellular telephony (including video

telephony)

– 4G: IP-based “anytime, anywhere” voice, data, and

multimedia telephony at faster data rates than 3G

(to be deployed in 2012–2015)

GSM Services• Voice, 3.1 kHz

• Short Message Service (SMS) – 1985 GSM standard that allows messages of at most 160 chars. (incl.

spaces) to be sent between handsets and other stations

– Over 2.4 billion people use it; multi-billion $ industry

• General Packet Radio Service (GPRS)– GSM upgrade that provides IP-based packet data transmission up to

114 kbps

– Users can “simultaneously” make calls and send data

– GPRS provides “always on” Internet access and the Multimedia Messaging Service (MMS) whereby users can send rich text, audio,video messages to each other

– Performance degrades as number of users increase

– GPRS is an example of 2.5G telephony – 2G service similar to 3G

Data transfer in GSM• The "data over cellular" bearer services are part of the

Phase 2 implementation of GSM

• The basic data transfer technology is called CSD (Circuit Switched Data)

• A GSM network’s data transfer facility allows the digital equivalent of modem transmissions - known as data streaming - at data speeds of up to 9,600 bits per second in GSM900 and 14,400 bits per second inGSM1800 networks

GSM – frequency slots

GSM Frequencies• Originally designed on 900MHz range, now also

available on 800MHz, 1800MHz and 1900 MHz

ranges.

• Separate Uplink and Downlink frequencies

– One example channel on the 1800 MHz frequency band,

where RF carriers are space every 200 MHz

1710 MHz 1880 MHz1805 MHz1785 MHz

UPLINK FREQUENCIES DOWNLINK FREQUENCIES

UPLINK AND DOWNLINK FREQUENCY SEPARATED BY 95MHZ

Data bursts – Normal burst• Modulation used in GSM is GMSK -> 270kb/s

GSM Architecture

Data transfer in GSM


UMTS3G

HSCSD

GPRS

EDGE

2.5G

CSD2G

Data transfer standardMobile telephony generation


LTE Advanced

WiMAX4G

HSDPA

HSUPA

HSPA+

LTE

3.5G

Data transfer standardMobile telephony generation

GSM 2.5G+ standards

HSCSD

• High-speed circuit-switched data (HSCSD), is an enhancement to circuit switched data (CSD), with data rates up to 57.6 kbit/s

• Channel allocation is done in circuit-switched mode, as with CSD

• Higher speeds are achieved as a result of superior coding methods, and the ability to use multiple time slots to increase data throughput (up to 4 slots)

HSCSD

• Pro:– Flexible bearer service (BS) for higher data rates

up to 57.6kb/s (1800MHz) or 38.4kb/s (900MHz)

– Transparent and non-transparent bearer services

– Rate adaptation for several standard interfaces incl. X.30/V.110, V.24, etc.

HSCSD

• Cons– Circuit-switched access, which is often

inefficient for data services that are bursty in nature

– Higher call blocking probability due to multi-slotallocation

– Possible high cost of service as it competes with voice service for the same resources

GPRS• General packet radio service (GPRS) is a

packet oriented mobile data service

• It is available both in 2G and 3G networks

• In 2G systems, GPRS provides data rates of 56-114 kbit/second

• Allows for efficient use of the bandwidth(statistical multiplexing)

• Circuit switching & Packet switching can be used in parallel

GPRS – statistical multiplexing

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GPRS - Features

• Constant connectivity

• GPRS is an overlay network over GSM

• Billing based on volume of data transferred

• GPRS uses radio channel 200kHz wide carring271kbps of data

• This is divided into 8 slots 34kbps each (14.4 kbps after corrections)

• 8*14.4 = 114kbps

GPRS - Coding

• GMSK and channel encoding based on a convolutional code used

• Four coding schemes:– CS-1 – speed: 8.0 kb/s per slot

– CS-2 – speed: 12.0 kb/s per slot



GPRS Terminals

• Class A:– MS supports simultaneous operation of GPRS

and GSM services

• Class B:– MS able to register to both services but works

only in a chosen one

• Class C:– MS works either in GPRS or in GSM mode

EDGE

• Enhanced Data rates for GSM Evolution (EDGE) is further improvement of data transmission in GSM networks

• Packet switched technology

• Main difference comparing to GPRS is thechange of modulation technology: fromGMSK to 8PSK

• Performance sensitive to radio conditions

Influence of EDGE on the GSM

network structure

EDGE - modulation

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EDGE - performance

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UMTS

• UMTS - Universal Mobile Telecommunications System is part of 3G and 4G systems

• Unlike previously described techniquesUMTS requires new base stations and new frequency allocations

• UMTS network is very similar to GSM

• The most common form of UMTS uses W-CDMA but also TD-CDMA and TD-SCDMA

UMTS – Network architecture

• RNC – Radio Network Controller

UMTS modes

• UMTS works in two modes – UMTS–FDD orUMTS-TDD

• In both modes there are used:– CDMA

– QPSK modulation

– Multiple channel coding and bearer rates

– Asynchronous operation

• Data rate up to 2 Mbps

UMTS - Features• Full packet driven architecture

– For voice and data transmission

– Packet based networks allow for an increased amountof traffic on a medium

– The only time that part of the medium is blocked isduring transmission/reception

• Services

UMTS - Features

• UMTS supports maximum theoretical data transfer rates of 42 Mbit/s (with HSPA+)

• At the moment users in deployed networks can expect a transfer rate of up to 384 kbit/sfor R99 handsets, and 7.2 Mbit/s for HSDPA handsets in the downlink connection

UMTS - Features

• Data rates over radio interface:– 2Mbps in fixed or in-building environments

– 384kbps in pedestrian or urban environments

– 144kbps in wide area mobile environments

– Variable data rates in large geographic areasystems (satellites)

UMTS – Data rates

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HSDPA

• HSDPA - High-Speed Downlink Packet Access - is an enhanced 3G (third generation) mobile telephony communications protocol in the High-Speed Packet Access (HSPA) family

• HSDPA allows for higher data rates in UMTS networks

• Current HSDPA deployments support down-link speeds of 1.8, 3.6, 7.2 and 14.0 Mbit/s

HSDPA

• The first phase of HSDPA has been specified in the 3rd Generation Partnership Project (3GPP) release 5:– Up to 14Mbps

• The second phase of HSDPA is specified in the 3GPP release 7 and has been named HSPA Evolved:– Up to 42Mbps

– MIMO

HSDPA

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HSDPA - Features

• Fast downstream throughput:– Data rates up to 10 Mbps

– Peak data rates even 14Mbps, with MIMO even~20Mbps

• Significant capacity increase (vs UMTS):– 3-4 times improved system capacity

– 1-2 times improvement for „best-effort” packetdata

– Improved capacity for streaming services (50%)

HSDPA – How it is done

• Adapting to environment with adaptivemodualtion and coding

• Fast channel scheduling with fast qualityfeedback

• MIMO

• Fast retransmissions

• Higher order modulations (QPSK+16QAM)

• More efficient processing

HSDPA – Categories

HSUPA

• HSUPA - High-Speed Uplink Packet Access - is an enhanced 3G (third generation) mobile telephony communications protocol in the High-Speed Packet Access (HSPA) family

• HSUPA allows for higher data rates in UMTS networks

• Current HSUPA deployments support up-link speeds up to 5.76 Mbit/s

• Works similar to HSDPA but in uplinkdirection

HSPA+

• HSPA - Evolved High-Speed Packet Access (HSPA) family

• Provides provides HSPA data rates up to 56 Mbit/s on the downlink and 22 Mbit/s on the uplink with MIMO technologies and higher order modulation (64QAM)

• The 56 Mbit/s and 22 Mbit/s represent theoretical peak sector speeds. The actual speed for a user will be lower

HSPA+

• Main enhancements in comparison to HSPA:– 64QAM in DL with (1x2) SIMO

– 16QAM in DL with (2x2) MIMO

– 16QAM in UL

– 64QAM in DL with (2x2) MIMO

HSPA+ vs WiMAX

HSPA+ vs WiMAX

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Comparison of LTE Speed

LTE• LTE - Long Term Evolution - is the latest

standard in the mobile network technology tree

• The LTE bases on a another radio interface thanGSM/UMTS networks

• Uses Orthogonal Frequency Division Multiplexing (OFDM) for downlink

• Uses Single Carrier Frequency Division Multiple Access (SC-FDMA) for uplink

• Uses Multi-input Multi-output(MIMO) for enhanced throughput

LTE - features• High spectral efficiency

– OFDM in Downlink, Robust against multipath interference & High

affinity to advanced techniques such as Frequency domain channel-

dependent scheduling & MIMO

– DFTS-OFDM (“Single-Carrier FDMA”) in Uplink, Low PAPR, User

orthogonality in frequency domain

– Multi-antenna application

• Very low latency

– Short setup time & Short transfer delay

• Support of variable bandwidth

– 1.4, 3, 5, 10, 15 and 20 MHz

Advantages of LTE

LTE – Major Parameters

LTE – User Equipement Categories

LTE Advanced

LTE vs LTE Advanced

LTE Advanced

• LTE Advanced – evolution of LTE towardsimproved data bandwidth

• LTE Advanced – 3GPP project Releases 10 andbeyond

• Finalized by 3GPP in March 2011

• LTE Advanced is backward compatible with LTE

• 100 MHz aggregated bandwidth

• 3.3 Gbit peak download rates per sector of the base station under ideal conditions

LTE Advanced - features• Coordinated multipoint (CoMP) transmission

and reception

• UE Dual TX antenna solutions for SU-MIMO anddiversity MIMO

• Scalable system bandwidth exceeding 20 MHz, up to 100 MHz

• Carrier aggregation of contiguous and non-contiguous spectrum allocations

• Flexible spectrum usage

• Cognitive radio

LTE Advanced - features• Automatic and autonomous network

configuration and operation

• Support of autonomous network and devicetest, measurement tied to networkmanagement and optimization

• Enhanced precoding and forward errorcorrection

• Interference management and suppression

• Asymmetric bandwidth assignment for FDD

• Hybrid OFDMA and SC-FDMA in uplink

• SONs, Self Organized Networks methodologies

• Multiple carrier spectrum access.

Application example

GSM module - features• Tri-band GSM/GPRS SMT module

• Size 33x33x3 mm !

• An embedded TCP/IP protocol stack

• Control via AT command

• Supply voltage 3.4 … 4.5 V

• Data rates:– GPRS: 85.6 kbps in downlink

– CSD up to 14.4 kbps

• Many interfaces: SPI, GPIO, antena, SIM card, serial interface, 2 x analog audio interface

Thank you for your attention

References[1] www.wikipedia.org

[2] Lundmark T., „ WiMAX - a sneak preview”, TietoEnator

[3] Michaud F., „GPRS & EDGE « First steps toward Wireless data »”

[4] Sridhar Iyer, „ WiMAX: IEEE 802.16 - Wireless MANs”,

http://www.it.iitb.ac.in/~sri

[5] http://www.rfcafe.com/references/electrical/gsm-specs.htm

[6] http://gsmfordummies.com/tdma/tdma.shtml

[7] http://www.transanatolia.eu/analyses/wireless%20networks/edge1.pdf

[8]

http://www.cs.ucy.ac.cy/courses/EPL657/pitsillides_slides_2009/EPL%206

57%20UMTS-protocols%20and%20architecture.pdf

[9] http://cp.literature.agilent.com/litweb/pdf/5990-6706EN.pdf

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