High Speed Downlink Packet Access (HSDPA) Essay

High Speed Downlink Packet Access ( HSDPA )

Abstraction

The rubric for the study is High Speed Downlink Packet Access ( HSDPA ) . Internet is become apart of our every twenty-four hours life and nomadic users demand for high velocity entree while they are on the move. HSDPA can carry through these demands and offer more services which are broadband related. The study will analyze and measure the HSDPA engineering, which include the architecture, protocols and protocol position. Besides the study discuss HSDPA rule operation and the physical and MAC bed. With Small graduated table simulation, HSDPA public presentation and how it manage different types of traffic and users, will be analyse. Besides the study will discourse the mentality market and how it compete with other similar engineerings in the coming old ages. By the terminal of my study I will derive more cognition and apprehension of HSDPA engineering and how much Mobile users and concern can profit from it.

Abbreviations

AES Advance Encryption Standard

AMC Adaptive Modulation and Coding

BTS Base Transceiver Station

DCH Dedicated Channel

DES Data Encryption Standard

DTX Discontinuous Transmission

DSL Digital Subscriber Line

FACH Fast Access Channel

GSM Global System for Mobile Communication

UMTS Universal Mobile Telecommunication System

3G Third Generation

WCDMA Wideband codification Division Multiple Access

HSDPA High Speed Downlink Packet Access

HSPA High Speed Packet Access

EDGE Enhanced Data Rate for Global Evolution

HS-DSCH High-speed Downlink Shared Channel

VoIP Voice over IP

TTI Transmission Time Interval

HARQ Hybrid Automatic Response petition

RRM Radio resource Management

SRNC Serving Radio Network Controller

RNC Radio Network Controller

RRC Radio Resource Control

PDCP Packet Data Convergence Protocol

RCL Radio Link Layer

MAC Medium Access Control

RACH Random Access Channel

S-CCPCH Secondary Common Control Physical Channel

HS-DSCH High Speed Downlink Shared Channel

HS-DPCCH High-speed dedicated Physical Control Channel

F-DPCH Fractional Dedicated Physical Channel

HS-PDSCH High-speed physical downlink shared channel

EAPOL Extensible Authentication Protocol over LANs

WEP Wired Equivalent Privacy

EAP Extensible Authentication Protocol

RSNA Robust Security Network Association

QoS Quality of Service

1.0 Introduction

Universal Mobile Telecommunication System ( UMTS ) is most turning nomadic engineering in the recent old ages. Resulting of that turning of figure of services such as nomadic Television, Multimedia and on-line games picture and picture cyclosis, which will demand a high velocity informations rate. Current 2.5G and 3G service suppliers are describing that a big proportion of use is due to informations, and the demand for the high velocity informations rate will increase specially for multimedia services. Recent Release 99 WCDMA has a upper limit of 384 kbps informations rate, which will be increased to 512 kbps and beyond. Then the debut of High Speed Downlink Packet Access ( HSDPA ) , which will hike WCDMA velocity and public presentation. HSDPA has better throughput than WCDMA and it has a higher information rate.

HSDPA is defers from W-CDMA, it uses a high-velocity downlink shared channel ( HS-DSCH ) , which has faster downlink velocity, transporting informations to mobile phones.

High Speed Downlink Packet Access is nomadic communications protocol, based on, and leveraging engineerings from the bing W-CDMA protocol. HSDPA aims to convey high-velocity informations communicating velocities more inline with those of standard consumer broadband services.

Execution of HSDPA can be done in the bing UMTS webs and it can work a long side the 3G webs based on the 3GPP Release 99. there is no demand of altering the 3G ‘s nucleus web every bit long as it can manage HSDPA traffic.

HSDPA sometimes referred to as 3.5G, will be able to offer theoretical download velocities of about 1.8Mbps, and upload velocities of 384Mbps. higher communicating velocities will shortly be possible with progresss in engineering. Comparable 3G informations communications devices.

HSDPA provides a important addition in high velocity nomadic communications from its predecessor.

HSDPA faculties can now be easy implemented in nomadic computing machines, utilizing either a PC-Card or internal mini-card device. So planing the engineering into a nomadic computing machine is non hard for the maker. The high velocity communications of HSDPA allows for a much richer Internet experience for the nomadic user. High velocity transmittal of Video and voice can be transmitted at higher velocities with small loss of quality.

This besides opens up nomadic Voice Over IP ( VoIP ) to the consumer. Sending Voice over an Internet connexion is surely cheaper than doing a long distance call, and is certain to be the future method of nomadic communications as service suppliers look to implement these solutions for their clients.

The nomadic work force ( going gross revenues people, international concern executives ) is the obvious donee of such engineerings, but HSDPA can hold important benefits for other users excessively. HSDPA provides high velocity broadband entree enemy users and concern remote locations who may non hold entree to traditional broadband entree methods.

HSDPA uses a figure of new techniques which provide a good betterment in public presentation for nomadic users and service suppliers.

2.0 HSDPA architecture

2.1 Radio resource Management ( RRM )

In HSDPA the programming control has been moved to BTS and that has overall alteration in RRM architecture. SRNC has control of handover, which is simplified in the sense that there is no soft handover for HSDPA informations. Then there is no demand to run user informations over multiple Iub and Iur interventions, even the use of the Iur intervention can be avoided by executing SRNC resettlement, when the functioning HS-DSCH cell under different commanding RNC.

2.2 Protocol architecture

The protocol architecture can be define as user plane portion, which handle all user informations, and command plane portion.

* Radio Resource Control ( RRC ) bed handles all the signalling related to configuring the channels, mobility direction, etc.

* PDCP is the Packet Data Convergence Protocol, has as its chief functionality heading compaction which is non relevant for circuit-switched services.

* Radio Link Layer ( RCL ) handles the cleavage and retransmission for both user and command informations.

· Medium Access Control ( MAC ) handles all function between the logical channels and the precedences, every bit good as choice of the information rates being used.

2.3 Protocol provinces with HSDPA

* Cell_DCH is the province which is used when active informations transmittal to and from the terminus on the DCH or HSDPA is possible.

* Cell_FACH province, which informations can be transmitted in this province, utilizing FACH for the downlink and RACH in the uplink, which means limited informations rates these channels do non offer any public presentation sweetening characteristics of HSDPA.

* Cell_PCH / URA_PCH province, these provinces are the most efficient 1s from the terminal battery ingestion point of position.

3.0 HSDPA Principles

HSDPA uses a figure of new engineerings which taking to increase capacity and throughput and better the overall system efficiency.

3.1 HSDPA Technologies

In Release 99 Specifications there are three different methods for downlink package informations operation:

The FACH is used to transport the signalling when the terminus has moved due to inaction. It is operated on its ain and depending on the terminus is in. FACH is decoded either continuously or based on the paging message. For the FACH there neither fast power control nor soft handover. FACH is carried on the secondary common control physical channel ( S-CCPCH ) with fixed distributing factor.

The DCH has fixed a distributing factor in the downlink with fixed allotment during the connexion. It can be used for any sort of service. HSDPA is ever operated with the DCH running in analogue.

HSDPA introduced new channels ( HS-DSCH ) for user informations and ( HS-SCCH ) in the downlink and ( HS-DPCCH ) in the uplink. Besides in Release 6 specification there is a new channel called fractional dedicated physical channel ( F-DPCH ) , which cover for operation when all downlink traffic is carried on the HS-DSCH.

The general HSDPA operation rule is shown in below, where Node B estimates the channel quality of each active HSDPA user on the footing of the physical bed feedback received in the uplink. Scheduling and associate version are so conducted at a fast gait depending on the programming algorithm and user prioritization strategy.

The other cardinal new engineering is physical bed retransmission. The package is received in the buffer in the BTS and kept at that place, if there any package decryption failure, retransmission automatically takes topographic point from the base station without RNC engagement.

3.1.1 High-speed downlink shared channel ( HS-DSCH )

HS-DSCH is defined as a conveyance channel which carries the user informations in HSDPA. Its has 2 MS TTI, which help to cut down unit of ammunition trip hold between UE and Node B. this allow a UE to hold minimum steady degree of informations rate all the clip. In the physical bed HS-DSCH is mapped to high-speed physical downlink shared channel ( HS-PDSCH ) . HS-DSCH has the fluxing belongingss:

* Link version and the usage of different cryptography and transition.

* Support of higher order transition.

* User allotment with BTS based programming every 2 MSs, with fast physical bed signalling.

* Use of physical bed retransmissions and retransmission combine.

* Multimode operation with fixed distributing factor, merely SF 16 is used.

* Use of turbo-coding

* No discontinuous transmittal ( DTX )

3.1.2 Higher Order Transition

Beside QPSK transition, HSDPA uses 16QAM transition which allow 4 spots can be carried per symbol, alternatively of 2 spots per symbol with QPSK transition. This mean with

higher order transition we can direct more informations on a individual channel

3.1.3 Fast Link Adaptation

HSDPA uses fast link version to change the sum of coding mistake generated by wireless channel coding strategy. This is done by altering and changing the cryptography and transition harmonizing to nexus or channel status, which will better informations rate and signal quality.

3.1.4 Hybrid Automatic Repeat Request

3.2.1 HS-DSCH cryptography

HS-DSCH usage merely turbo-coding. The channel cryptography concatenation is simplified and merely transport channel active at a clip. An extra new issue is the handling of 16QAM and the ensuing variable figure of spots carried by the physical channel even the figure of codifications used remains fixed.

3.3 High-speed shared control channel ( HS-SCCH )

HS-SCCH carries time-critical signalling information which allows the terminus to demodulate the right codifications. There are no pilots or power control bits on the HS-SCCH, so the stage mention is ever the same as for the HS-DSCH. HS-SCCH is divided into two parts:

* The first portion carries information needed to enable de-spreading of the right codification and contains the transition information.

* The 2nd portion contains less pressing information, such as which ARQ procedure is being transmitted.

3.4 High-speed dedicated physical control channel ( HS-DPCCH )

HS-DPCCH carries the uplink feedback information from the terminus to the BTS to enable the nexus version and physical bed retransmissions. It has fixed distributing factor of 256 and 2 MSs / three-slot construction. HS-DPCCH operation has been enhanced in release 6 to better cell border operation.

3.4.1 Fractional DPCH ( F-DPCH )

F-DPCH is a stripped-down version of DPCH that handle the power control. The codification resource is time-shared and several users can portion the same codification infinite for power control information. It has some limitations: non useable with services necessitating informations to be mapped to the DCH, feedback-based transmit diverseness is non useable.

3.4.2 HS-DSCH Link version

Link version is really dynamic as it operates with 2 MSs coarseness with the HS-DSCH. It is based on physical bed CQI being provided by the terminus. By utilizing link version, the web will derive from the restriction of power control kineticss in the downlink.

3.4.3 Physical bed operation

HSDPA physical bed operation goes through the undermentioned stairss one time one or more users have been cond as utilizing the HS-DSCH and informations start to make the buffer in the Node B.

* Node B evaluate channel status, buffer position, clip from last transmittal, transmittal pending and so forth for each user every 2 MS.

* The Node B identifies the necessary HS-DSCH parametric quantities, including figure of codifications, 16QAM serviceability and terminal capableness restrictions.

* The Node B starts to convey the HS-SCCH two slots before the corresponding HS-DSCH TTI.

* The terminal proctors the terminal-specific set of at most four HS-SCCHs given by the web. Once the terminus has decoded Part 1 from an HS-SCCH, it will get down to decrypt the staying parts and will buffer the necessary codifications from the HS-DSCH.

* After decrypting the HS-SCCH parametric quantities from Part 2, the terminus can find to which ARQ procedure the information belong and whether they need to be combined with informations already in the soft buffer.

* In the Release 6 version, a pre-amble is sent in the ACK/NACK field if the characteristic is cond to be used by the web.

* Upon decrypting the potentially combined informations, the terminal sends in the uplink way an ACK/NACK index, depending on the result of the CRC conducted on the HS-DSCH informations.

* If the web continues to convey informations for the same terminus in back-to-back TTIs, the terminus will remain on the same HS-SCCH that was used during the pervious TTI.

* In Release 6, when the information flow terminal, the terminal sends a post-amble in the ACK/NACK field.

HSDPA basic characteristics

1 ) Adaptive Coding and Modulation

The rule of ACM is to change the cryptography and transition for transmittal harmonizing to the status of the receiving system channel.

2 ) Hybrid Automatic Repeat Request ( HARQ )

When receiving system can non decrypt informations because of informations mistake, HARQ chief occupation is retransmitting the information.

3 ) The Active clip Space Priority ( TSP )

TSP manage and control packages in the buffer of base station.

3.0 HSDPA Performance

HSDPA has a high information rate of 10 Mbit/s in normal 5 MHz channel, besides its fast shift capableness ( 2 MS ) increases trunking efficiency for high informations rate package service. HSDPA high order transition can be used to increase user throughput and better cell capacity. Besides fast package scheduling gives a high cell capacity and maintain needed QoS.

There are several factors that consequence HSDPA public presentation and here some of them:

* Network algorithms, specific algorithms such as MAC-hs package scheduler, HS-DSCH nexus version, HS-SCCH power control and HSDPA transmittal resource allotment.

* UE sensor public presentation and capableness, such as peak information rate, figure of HS-PDSCH channel codifications, figure of transmit and receive aerials, and baseband receiving system algorithms.

* Traffic and quality of service ( QoS ) , such as figure of active users, and their corresponding QoS demands.

* Channel status which include the environment of the cell itself, clip scattering, ain cell intervention and other cell illation.

3.1 Single-user Performance

QPSK ( Quarter stage displacement identifying ) transition is used when is merely one HS-PDSCH codification is used, so there is less power required per user spot and the consequence is low informations rate. Other factors that consequence single-user public presentation are transmittal, processing holds and the Channel Quality Indicator ( CQI ) . Indoor user with microcell in usage, channel quality will be good and so the information rate, because of less clip scattering and intervention. In the other manus, outdoor user utilizing macro cell, and because of high clip scattering and other cell intervention, peak information rate is limited. Data coverage is low because there is no exchanging addition in individual user state of affairs, but overall cell capacity has a addition from soft handover.

3.2 Multiple-user Performance

The usage of fast package programming, in multiple user environments, has a great consequence on the cell throughput and the needed QoS by the terminal user. The throughput addition straight related to the figure of users utilizing the same HS-DSCH channel and the intervention ratio. Note that when the of users addition, per user throughput lessenings because HS-DSCH capacity is shared between users.

HSDPA uses different types of scheduling methods and here are some of them ;

* Round redbreast and just package scheduler ; this method dose non take count of channel status and agenda users the best instantaneous channel quality.

* Proportional carnival algorithm which offers an attractive trade off between user equity and cell capacity, and used when users have good instantaneous channel status. The method better user and cell throughput [ 1 ] .

4 HSDPA vs. WiMax

4.1 Coverage and spot rates

WiMAX scope coverage can make up to 50 kilometers, with bandwidth up to 70 Mbit/s, but the existent bandwidth is lower than the above and still capable to debate. WiBro has a information rate up to 30 Mbit/s, which gives users downlink informations rate up to 18 Mbit/s and 6 Mbit/s on the uplink. But signal is acquiring weaker when distance between UE and BTS is big, because the signal over noise ratio is decrease quicker as distance addition. Besides WiMAX BTS ‘s can pass on with each other even without line of sight.

In HSDPA system, downlink bandwidth can make up to 14.4 Mbps at distance less than 1km, and 384 kbit/s on the uplink, but bandwidth bead as distance addition, same as in WiMAX system. but users can convey informations even with really low bandwidth.

4.2 Capacity

HSDPA engineering is design for coincident users, tonss users can portion channels and bandwidth. If figure of users addition, the system can still get by but with low informations rate.

WiMAX can merely run with few tonss of users and the web can non get by when figure of users addition.

4.3 Multimedia capableness

For both HSDPA and WiMAX, there is similarities in multimedia capableness and capacity and both have QoS multimedia applications.

4.4 Security characteristics

HSDPA authenticate users through their SIM card which include two manner challenge, encoding of signalling traffic, usage of two manner hallmark of 3G web and encoding on wireless nexus. and does non hold any other security characteristic. Data encoding for different users, typical of all CDMA criterions, works better than any cryptanalytic algorithm, but non if an interloper is in a base station or somehow gets its channels codification. WiMAX supports modern cryptanalytic algorithms, such as AES and DES. It uses X.509 certification and EAP. It will surely delight corporate users, who want to maintain their informations in secret.

Mobile WiMAX

HSDPA

Date of debut

2008-9

2006-7

Downlink informations rate ( soap )

23 Mbit/s

14.4 Mbit/s

Uplink informations rate ( soap )

4 Mbit/s

384 kbit/s

Rotational latency

50 MS

100 MS

Security

Certificate or EAP

SIM-based security

Spectrum

2.3 GHz, new at 2.5 GHz

3G 2 GHz, new at 2.5 GHz

Service set-up clip

50 MS

2 unsweet cut downing to 0.6 esc

Table: Comparison of WiMAX and HSDPA ( BT Technology Journal [ 6 ] )

5 Market Outlook for HSDPA

Internet market is turning quickly, in recent old ages, specially nomadic broadband, which provide cyberspace for users either on the move or in distant countries where they can non acquire entree to traditional broadband entree. In 2009, more than 250 HSDPA webs went on-line providing broadband services across the Earth, with velocity up to 42Mbit/s. the figure of broadband endorsers are increasing quickly, and by terminal of twelvemonth 2013 the entire endorsers will be more than 30 % of whole nomadic users.

The execution of HSDPA does non necessitate constructing a new web substructure, it can be done with bing 3G web with better coverage and really effectual and efficient usage of bandwidth. So turn overing out HSDPA services can done rapidly and be efficaciously driven by users demand for such service.

Personal computer card are the first HSDPA device, it can be slotted into desktop or laptop giving users high velocity cyberspace broadband connexion. Then it moved on to USB modems, and now laptop and nomadic phones come with built in HSDPA capableness. Besides HSDPA service can be provided through landline Ethernet and Wi-Fi.

5.1 UK Market

The debut of nomadic broadband services is enabled by HSDPA engineering in 3G nomadic webs, that enables laptop utilizations to entree the Internet on the move at velocities of up to 1.8 Mbit/s, similar to ADSL and overseas telegram modem broadband services. Vodafone was the first UK Mobile Operator to lunch HSDPA service in 2006, which offer subscriber nomadic broadband with velocity up 2Mbps and monthly fee of ?45, with maximal use of one Gbyte per month. Now all operators in the UK are offering HSDPA service with mean monetary value of ?10 to ?15 a month and maximal download of 2 Gbyte. That average endorsers are paying norm of ?0.025 per Mb. Besides some operators are offering free WiFi use.

Now, Vodafone offering nomadic broadband with maximal velocity of 8Mb, and working in upgrading its web to maximum velocity of 14.4 Mb. This will do Vodafone the first operator to offer highest downlink velocity, but in existent life this velocity will ne’er be true. Other United kingdom operators are offering a lower velocity, T Mobile offering nomadic broadband with velocity up to 4.5Mbp/s, O2, Orange and Three are offering velocity of up 3.6Mbp/s and they are still working to upgrade their web to suit velocity of 7Mbp/s.

5.2 International Market

HSDPA can be implemented on 3G webs and there no demand for constructing new substructure, this brand of turn overing out HSDPA a caput of its rival. Number of endorsers are reach the 1 Billion in commercial HSPA enabled webs, with figure of 204 HSDPA operator in 89 states, has been reported. With 35 webs in APAC part, 61 webs in Western Europe, 34 webs in Eastern Europe, 16 webs in the USA and Caribbean and 20 webs in Middle East and Africa [ 7 ] .

6 Decision

HSDPA is the new coevals in the nomadic broadband engineering, which has a higher information rate and faster cyberspace entree. HSDPA dose non necessitate constructing a new webs and it can be implemented on the bing 3G webs. Mobile operators still working difficult and assure their clients to upgrade their webs to exceed maximal downlink velocity of 14.4Mbit/s, while maintaining their monetary values down. But HSDPA confronting a large competition from similar engineerings such as WiMAX, which offer maximal downlink speed up to 23Mbit/s. HSDPA has a good mobility, voice and informations from cellular platform.

7 Mentions

1 Harri Holma and Antti Toskala, WCDMA for UMTS: HSPA Evolution and LTE, 4th edition, Wiley 2007

2 Harri Holma and Antti Toskala, HSDPA/HSUPA for UMTS: High Speed Radio Access for Mobile Communications, Wiley 2006

3 Byeong Gi Lee and Sunghyun, “Broadband Wireless Access and Local Networks: Mobile WiMAX and WiFi, Artech House 2008

4 Nokia HSDPA Solution, [ online ] , visited on 28/2/10, available at hypertext transfer protocol: //nds2.ir.nokia.com/NOKIA_COM_1/About_Nokia/Press/WhitePapers/pdf_files/HSDPA

5 WCDMA and WLAN for 3G and beyond, [ online ] , visited on 1/3/10, available at hypertext transfer protocol: //ieeexplore.ieee.org/Xplore/login.jsp? url=http % 3A % 2F % 2Fieeexplore.ieee.org % 2Fstamp % 2Fstamp.jsp % 3Ftp % 3D % 26arnumber % 3D998520 % 26isnumber % 3D21543 & A ; authDecision=-203

6 N Johnston and H Aghvami, comparing WiMAX and HSDPA, a usher to the engineering, BT Technology Journal, Vol. 25 No. 2 April 2007.

7 HSPA is Global system of pick for nomadic broadband, GSA study, [ online ] , visted on 3/3/10, available at hypertext transfer protocol: //www.mobileeurope.co.uk/news_wire/113504/GSA_survey_said_to_confirm_HSPA_as_global_system_of_choice_for_mobile_broadband.html