HSPA+ Evolution: Standards and Data Rates

From the 4G Americas white paper.

3GPP System Building on Releases

Evolution of 3GPP Security

New 4G Americas whitepaper on HSPA evolution in 3GPP standards

Some forecasts put HSPA at over 3.5 billion subscribers by the end of 2016. Operators with HSPA and LTE infrastructure and users with HSPA and LTE multi-mode devices will be commonplace. There are 412 commercial deployments of HSPA in 157 countries, including 165 HSPA+ networks. Thus, with the continued deployment of LTE throughout the world, and the existing ubiquitous coverage of HSPA in the world, HSPA+ will continue to be enhanced through the 3GPP standards process to provide a seamless solution for operators as they upgrade their networks. While LTE, with 33 commercial deployments to date and over 250 commitments worldwide, will be the mobile broadband next generation technology of choice for HSPA, EV-DO, WiMAX and new wireless operators, HSPA will continue to be a pivotal technology in providing mobile broadband to subscribers.

The white paper explains that as 3GPP specifications evolve, their advanced features help to further the capabilities of today’s modern mobile broadband networks. With each release there have been improvements such as better cell edge performance, increased system efficiencies, higher peak data rates and an overall improved end-user experience. 3GPP feature evolution from Rel-7 to Rel-10 has pushed possible HSPA peak data rates from 14 Mbps to 168 Mbps. Continued enhancements in 3GPP Rel-11 will again double this capability to a possible peak data rate of 336 Mbps:

• Rel-7: 64QAM or 2X2 MIMO => 21 or 28 Mbps
• Rel-8: DC + 64QAM or 2X2 MIMO + 64QAM => 42 Mbps
• Rel-9: DC + 2X2 MIMO + 64QAM => 84 Mbps
• Rel-10: 4C + 2X2 MIMO + 64QAM => 168 Mbps
• Rel-11: (8C or 4X4 MIMO) + 64QAM => 336 Mbps

“If operators are able to gain new additional harmonized spectrum from governments, they will no doubt deploy LTE, However, it is clear that HSPA+ technology is still exceptionally strong and will continue to provide operators with the capability to meet the exploding data usage demands of their customers in existing spectrum holdings,” Pearson said.

The paper is embedded as follows:

The Evolution of HSPA

View more documents from All About 4G

This paper and other similar papers are available to download from the 3G4G website here.

Multimedia Telephony (MMTel) in 3GPP Rel-7

Came across MMTel multiple times in the last few months so decided to dig a bit more in detail.

The following from wikipedia:

The 3GPP/NGN IMS Multimedia Telephony Service (MMTel) is a global standard based on the IP Multimedia Subsystem (IMS), offering converged, fixed and mobile real-time multimedia communication using the media capabilities such as voice, real-time video, text, file transfer and sharing of pictures, audio and video clips. With MMTel, users have the capability to add and drop media during a session. You can start with chat, add voice (for instance Mobile VoIP), add another caller, add video, share media and transfer files, and drop any of these without losing or having to end the session.

The MMTel standard is a joint project between the 3GPP and ETSI/TISPAN standardization bodies. The MMTel standard is today the only global standard that defines an evolved telephony service that enables real-time multimedia communication with the characteristics of a telephony service over both fixed broadband, fixed narrowband and mobile access types. MMTel also provides a standardized Network-to-Network Interface (NNI). This allow operators to interconnect their networks which in turn enables users belonging to different operators to communicate with each other, using the full set of media capabilities and supplementary services defined within the MMTel service definition.

One of the main differences with the MMTel standard is that, in contrast of legacy circuit switched telephony services, IP transport is used over the mobile access. This means that the mobile access technologies that are in main focus for MMTel are access types such as High Speed Packet Access (HSPA), 3GPP Long Term Evolution (LTE) and EDGE Evolution that all are developed with efficient IP transport in mind.

MMTel allows a single SIP session to control virtually all MMTel supplementary services and MMTel media. All available media components can easily be accessed or activated within the session. Employing a single session for all media parts means that no additional sessions need to be set up to activate video, to add new users, or to start transferring a file. Even though it is possible to manage single-session user scenarios with several sessions – for instance, using a circuit-switched voice service that is complemented with a packet-switched video session, a messaging service or both – there are some concrete benefits to MMTel’s single-session approach. A single SIP session in an all-IP environment benefits conferencing; in particular, lip synchronization, which is quite complex when the voice part is carried over a circuit-switched service and the video part is carried over a packet-switched service. In fixed-mobile convergence scenarios, the single-session approach enables all media parts of the multimedia communication solution to interoperate.

An interesting presentation on MMTel is embedded below.

3GPP MMTel General Overview

View more presentations from Zahid Ghadialy

If you are still hungry for more on this topic then Ericsson's old presentation on MMTel is available on Slideshare here.

IMB and TDtv (and DVB-H)

Its long time since I blogged about TDtv. Its been quite a while since I heard about TDtv. Apparently its been superseded by IMB, aka. Integrated Mobile Broadcast.

IMB is used to stream live video and store popular content on the device for later consumption. This results in a significant offloading of data intensive traffic from existing 3G unicast networks and an improved customer experience. The multimedia client features an intuitive electronic program guide, channel grid and embedded video player for live TV viewing and video recording. All IMB applications can be quickly and cost-effectively adapted to support all major mobile operating systems and different mobile device types, including smartphones, tablets and e-readers.

IMB was defined in the 3GPP release 8 standards, and was recently endorsed by the GSMA as their preferred method for the efficient delivery of broadcast services. In June 2010, O2, Orange and Vodafone – three of the five major UK mobile operators – announced that they have teamed up for a three-month trial that will explore IMB wireless technology within a tranche of 3G TDD spectrum.

This spectrum already forms part of the 3G licenses held by many European mobile operators, but has remained largely unused because of a lack of appropriate technology. Currently, 3G TDD spectrum is available to over 150 operators across 60 countries, covering more than half a billion subscribers. IMB enables spectrally efficient delivery of broadcast services in the TDD spectrum based on techniques that are aligned with existing FDD WCDMA standards. This enables a smooth handover between IMB and existing 3G networks.

Issues that previously limited uptake of IMB, or IPWireless' tdTV system, have now all been addressed. Namely, the standard now allows for smooth handover between IMB and unicast delivery; has the potential to be integrated onto a single W-CDMA chip rather than requiring a separate chip; and has resolved interference issues with FDD W-CDMA, at least for spectrum in the 1900MHz to 1910MHz range.

IP Wireless already had a trial at Orange and T-Mobile in the UK (which have just agreed to merge), but in that pilot each 5MHz segment only gave rise to 14 TV channels per operator. The new standard could support 40 separate TV channels if two operators shared their TDD spectrum.

The GSMA announced its support and is backed up with additional support from both IPWireless and Ericsson as well as operators Orange, Softbank and Telstra.

There have been recently quite a few bad news for DVB-H and on top of that IP Wireless has announced that Samsung is going to be releasing phones with IMB support so it may be that we will see IMB sometime next year.

The GSMA paper that details IMB service scenarios and System requirements is embedded below:

Integrated Mobile Broadcast (IMB) Service Scenarios and System Requirements

View more documents from Zahid Ghadialy.

HSPA+ rollout updates, Jan 2010

It has been predicted that the growth of HSPA+ broadband across Europe is set to soar with the total number of subscribers set to nearly double across Europe in 2011.

A new report has predicted that by 2011 the growth of HSPA+ broadband across key European markets will soar, and could almost double compared to 2009. The number of subscribers is set to soar from twenty two million in 2009 to around forty three million in 2011. The report was released by CCS Insight.

According to the report HSPA+ broadband will be a major factor in seeing growth of one hundred percent in the to five major European markets. The report goes on to state that the European mobile broadband market will enjoy seeing both subscriber and revenue numbers double by 2011. Revenues are set to increase from around six billion Euros in 2009 to around eleven billion Euros in 2011.

Michael O’Hara, chief marketing officer at the GSMA, said: “It is clear from this report that with the right network investment, European mobile network operators will see significant growth in mobile broadband adoption in the next two years. HSPA technology will drive this rapid uptake across Europe as mobile operators and their customers continue to benefit from its expanding, vibrant and competitive ecosystem.”

HSPA+ was generally the most efficient way of upgrading use of bandwidth already in use and was likely to dominate in the short term at least, with an estimated 1.4 billion subscribers worldwide by 2013, around ten times the estimated take-up of LTE.

HSPA+ release 7, which became available last year, uses MIMO technology like that in 11n Wifi to help take the peak downlink throughput to 28Mbps, with 11Mbps on the uplink. Release 8, for which chipsets will become available this year, aggregates two carrier signals to bring peak data rates to 42Mbps on the downlink.

Release 9 will put two MIMO streams on each of two 5MHz carriers, aggregated to produce a 10MHz data pipe delivering 84Mbps on the downlink; the uplink uses simple aggregation to 23Mbps. A projected Release 10 would bring the peak downlink speed to 168Mbps, though this would require 20MHz carriers only available in the 2.5GHz and 2.6GHz bands.

Novatel Wireless, a developer of wireless data cards and other devices, said that it has added support for dual-carrier HSPA+ networks. The firm said it is using Qualcomm's MDM8220 chipset for the support, and will launch commercial devices in the second half of 2010 based on the chipset. Novatel said the new support will add more advanced data capability and other features to its offerings. Dual Carrier HSPA+ networks are expected to provide higher throughput to wireless data devices, and also helps address better service for cell phone users.

The new modem can receive data at up to 42M bps (bits per second) in compatible 3G networks. To increase the theoretical maximum download speed of the modem from 21M bps to 42M bps, Novatel uses two carrier frequencies instead of the usual one, a technique called dual-carrier. But it will only deliver the higher speed on networks that also support the technique.

Users can expect peak speeds at up to 30M bps, according to Hans Beijner, marketing manager for radio products at Ericsson.Leif-Olof Wallin, research vice president at Gartner, is a more pessimistic, saying increased traffic on the networks could negatively impact speeds. "I think it will be difficult to get above 20M bps," he said.

Sixty-six operators have said they plan to use HSPA Evolution, and so far 37 networks have been commercially launched, according to statistics from the Global Mobile Suppliers Association (GSA).

However, the version of HSPA Evolution that supports 42M bps is still very much in its infancy. Last week, mobile operator 3 Scandinavia announced plans to launch services when modems become available. In December, representatives from Vodafone and the Australian operator Telstra visited Ericsson to Stockholm to view a demonstration, but neither operator has so far announced plans to launch commercial services.

Ericsson and 3 Scandinavia have unveiled plans to roll-out a worlds-first 84Mbps HSPA+ wireless network. The initial rollout will cover Denmark and four Swedish cities. HSPA+ networks that currently operate in Canada, for example, offer speeds of up to 21Mbps depending on conditions. In the United States, T-Mobile recently announced a similar planned network.

Real-world tests of the 21Mbps networks show the services achieving around 7Mbps speed. If a similar performance could be applied to the new Ericsson/3 network, it could result in speeds of roughly 28Mbps at realistic distances and network load.

and 3 will also deploy 900MHz 3G networks in Sweden in a bid to boost coverage in remote areas, as existing higher frequency networks have left some users with poor performance.

The high-speed services will hit Denmark and areas of Sweden this winter if all goes to plan.

China Unicom is putting the finishing touch on the tests on its HSPA+ networks in Guangzhou, Shenzhen, and Zhuhai, which were kicked off in October 2009 by partnering with its three major suppliers Huawei Technologies, ZTE, and Ericsson.

HSPA+ is the next generation technology for China Unicom's WCDMA 3G service. HSPA+, also known as Evolved High-Speed Packet Access, is a wireless broadband standard defined in 3GPP release 7. The HSPA+ network claims with a transmission speed of 21Mbps, 1.5 times faster than its current 3G network.

The outdoor average speed of the networks built up by Ericsson and Huawei reach up to 16.5Mbps and 18.5Mbps on the downlink, 50% higher than that of the existing HSPA network. That means you can download a song within two or three seconds.

Cell C, South Africa, has signed a US$378m deal with the Chinese telecom equipment provider ZTE Corporation. Cell C would ever lead the industry as far as network infrastructure is concerned but it is a fact that Cell C will be the first South African operator to roll out HSPA+ technologies incorporating download speeds of up to 21Mbit/s – three times faster than anything currently available.

According to Cell C an important factor in the decision to appoint ZTE is its ability to offer 4G services using Cell C’s 900MHz frequency band which offers wider and deeper coverage than existing 2100 MHz networks, enabling cost effective deployment to rural as well as metropolitan areas.

Technologies and Standards for TD-SCDMA Evolutions to IMT-Advanced

Picture Source: http://www.itu.int/dms_pub/itu-t/oth/21/05/T21050000010003PDFE.pdf

This is a summary of a paper from IEEE Communications Magazine, Dec 2009 issue titled "Technologies and Standards for TD-SCDMA Evolutions to IMT-Advanced" by Mugen Peng and Wenbo Wang of Beijing University of Posts and Telecommunications with my own comments and understanding.

As I have blogged about in the past that China Mobile has launched TD-SCDMA network in China and the main focus to to iron out the basic problems before moving onto the evolved TD-SCDMA network. Couple of device manufacturers have already started working on the TD-HSPA devices. Couple of months back, 3G Americas published a whitepaper giving overview and emphasising the advantages of TDD flavour of LTE as compared to FDD. The next milestone is the IMT-Advanced that is under discussion at the moment and China has already proposed TD-LTE-Advanced which would be compatible with the TD-SCDMA technology.

For anyone who does not know the difference between TDD, FDD and TD-SCDMA please see this blog.

The TD-SCDMA technology has been standardised quite a while back but the rollout has been slow. The commercial TD-SCDMA network was rolled out in 2009 and more and more device manufacturers are getting interested in the technology. This could be due to the fact that China Mobile has a customer base of over 500 million subscribers. As of July 2009 over 100 device manufacturers were working on TD-SCDMA technology.

The big problem with TD-SCDMA (as in the case of R99 3G) is that the practical data rate is 350kbps max. This can definitely not provide a broadband experience. To increase the data rates there are two different approaches. First is the Short Term Evolution (STE) and the other is Long Term Evolution (LTE).

The first phase of evolution as can be seen in the picture above is the TD-STE. This consists of single carrier and multi-carrier TD-HSDPA/TD-HSUPA (TD-HSPA), TD-MBMS and TD-HSPA+.

The LTE part is known as TD-LTE. There is a definite evolution path specified from TD-SCDMA to TD-LTE and hence TD-LTE is widely supported by the TD-SCDMA technology device manufacturers and operators. The target of TD-LTE is to enhance the capabilities of coverage, service provision, and mobility support of TD-SCDMA. To save investment and make full use of the network infrastructure available, the design of TD-LTE takes into account the features of TD-SCDMA, and keeps TD-LTE backward compatible with TD-SCDMA and TD-STE systems to ensure smooth migration.

The final phase of evolution is the 4G technology or IMT-Advanced and the TD-SCDMA candidate for TD-LTE+ is TD-LTE-Advanced. Some mature techniques related to the TD-SCDMA characteristics, such as beamforming (BF), dynamic channel allocation, and uplink synchronization, will be creatively incorporated in the TD-LTE+ system.

Some academic proposals were also made like the one available here on the future evolution of TD-SCDMA but they lacked the industry requirements and are just useful for theoretical research.

The standards of TD-SCDMA and its evolution systems are supervised by 3GPP in Europe and by CCSA (Chinese Cellular Standards Association) in China. In March 2001 3GPP fulfilled TD-SCDMA low chip rate (LCR) standardization in Release 4 (R4). The improved R4 and Release 5 (R5) specifications have added some promising functions including HSDPA, synchronization procedures, terminal location (angle of arrival [AOA]-aided location), and so on.

When the industry standardizations supervised by CCSA are focusing on the integration of R4 and R5, the N-frequency TD-SCDMA and the extension of HSDPA from single- to multicarrier are presented. Meanwhile, some networking techniques, such as N-frequency, polarized smart antenna, and a new networking configuration with baseband unit plus remote radio unit (BBU+RRU), are present in the commercial application of TD-SCDMA.

TD-SCDMA STE

For the first evolution phase of TD-SCDMA, three alternative solutions are considered. The first one is compatible with WCDMA STE, which is based on HSDPA/HSUPA technology. The second is to provide MBMS service via the compatible multicast broadcast single-frequency network (MBSFN) technique or the new union time-slot network (UTN) technique. The last is HSPA+ to achieve similar performance as LTE.

On a single carrier, TD-HSDPA can reach a peak rate of 2.8 Mb/s for each carrier when the

ratio of upstream and downstream time slots is 1:5. The theoretical peak transmission rate of a three-carrier HSDPA system with 16-quadrature amplitude modulation (QAM) is up to 8.4 Mb/s.

Single-carrier TD-HSUPA can achieve different throughput rates if the configurations and parameters are varied, including the number of occupied time slots, the modulation, and the transport block size in bytes. Considering the complexity of a terminal with several carriers in TD-HSUPA, multicarrier is configured in the Node B, while only one carrier is employed in the terminal.

In Rel-7 based TD-HSPA+, In order to match the performance of orthogonal frequency-division multiple access (OFDMA)-based TD-LTE systems, some advanced techniques are utilized, such as multiple-input multiple-output (MIMO), polarized BF, higher modulation and coding schemes (64-QAM is available), adaptive fast scheduling, multicarrier techniques, and so on. Theoretically, 64-QAM can improve performance by a factor of 1.5 compared to the current 16-QAM; for single-carrier the peak rate reaches 4.2 Mb/s, and three-carrier up to 12.6 Mb/s.

For the MIMO technique, double transmit antenna array (D-TxAA), based on the pre-coding method at the transmitter, has been employed in frequency-division duplex (FDD)-HSPA+ systems, while selective per antenna rate control (S-PARC), motivated by the Shannon capacity limit for an open loop MIMO link, has been applied in TD-HSPA+ systems.

TD-SCDMA LTE

The TD-SCDMA LTE program was kicked off in November 2004, and the LTE demand report was approved in June 2005. The LTE specified for TD_SCDMA evolution is named TD-LTE.

LTE systems are supposed to work in both FDD and TDD modes. LTE TDD and FDD modes have been greatly harmonized in the sense that both modes share the same underlying framework, including radio access schemes OFDMA in downlink and SC-FDMA in uplink, basic subframe formats, configuration protocols, and so on.

TD-LTE trials have already started last year with some positive results.

TD-SCDMA LTE+

IMT-Advanced can be regarded as a B3G/4G standard, and the current TD-SCDMA standard migrating to IMT-Advanced can be regarded as a thorough revolution. TD-LTE advanced (TD-LTE+) is a good match with the TD-SCDMA revolution to IMT-Advanced.

It is predicted that the future TD-SCDMA revolution technology will support data rates up to approximately 100 Mb/s for high mobility and up to approximately 1 Gb/s for low mobility such as nomadic/local wireless access.

Recently, some advanced techniques have been presented for TD-LTE+ in China, ranging from the system architecture to the radio processing techniques, such as multi-user (MU)-BF, wireless relaying, and carrier aggregation (CA).

For MU-BF see the paper proposed by Huawei, CHina Mobile and CATT here (http://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_55b/Docs/R1-090133.zip).

For Wireless Relaying see the ZTE paper here (http://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_56b/Docs/R1-091423.zip).

To achieve higher performance and target peak data rates, LTE+ systems should support bandwidth greater than 20 MHz (e.g., up to 100 MHz). Consequently, the requirements for TD-LTE+ include support for larger transmission bandwidths than in TD-LTE. Moreover, there should be backward compatibility so that a TD-LTE user can work in TD-LTE+ networks. CA is a concept that can provide bandwidth scalability while maintaining backward compatibility with TD-LTE through any of the constituent carriers, where multiple component carriers are aggregated to the desired TD-LTE+ system bandwidth. A TD-LTE R8 terminal can receive one of these component carriers, while an TD-LTE+ terminal can simultaneously access multiple component carriers. Compared to other approaches, CA does not require extensive changes to the TD-LTE physical layer structure and simplifies reuse of existing implementations. For more on Carrier Aggregation see CATT, LGE and Motorola paper here (http://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_56b/Docs/R1-091655.zip).

Finally, there are some interesting developments happening in the TD-SCDMA market with bigger players getting interested. Once a critical mass is reached in the number of subscribers as well as the manufacturers I wouldnt be surprised if this technology is exported beyond the Chinese borders. With clear and defined evolution path this could be a win-win situation for everyone.

Flexible RLC in Release 7 and Release 8

In R99, RLC packets had to be relatively small to avoid the retransmission of very large packets in case of transmission errors. Another reason for the relatively small RLC packet size was the need to provide sufficiently small step sizes for adjusting the data rates for Release 99 channels.

The RLC packet size in Release 99 is not only small, but it is also fixed for Acknowledged Mode Data and there are just a limited number of block sizes in UM Data. This limitation is due to transport channel data rate limitations in Release 99. The RLC payload size is fixed to 40 bytes in Release 99 for Acknowledged Mode Data. The same RLC solution is applied to HSDPA Release 5 and HSUPA Release 6 as well: the 40-byte packets are transmitted from RNC to the base station for HSDPA. An additional confi guration option to use an 80-byte RLC packet size was introduced in Release 5 to avoid extensive RLC protocol overhead, L2 processing and RLC transmission window stalling. With the 2 ms TTI used with HSDPA this leads to possible data rates being multiples of 160 kbps and 320 kbps respectively.

As the data rates are further increased in Release 7, increasing the RLC packet size even further would significantly impact on the granularity of the data rates available for HSDPA scheduling and the possible minimum data rates.

3GPP HSDPA and HSUPA allow the optimization of the L2 operation since L1 retransmissions are used and the probability of L2 retransmissions is very low. Also, the Release 99 transport channel limitation does not apply to HSDPA/HSUPA since the L2 block sizes are independent of the transport formats. Therefore, it is possible to use fl exible and considerably larger RLC sizes and introduce segmentation to the Medium Access Control (MAC) layer in the base station.

This optimization is included for downlink in Release 7 and for uplink in Release 8 and it is called flexible RLC and MAC segmentation solution. The RLC block size in fl exible RLC solution can be as large as an Internet Protocol (IP) packet, which is typically 1500 bytes for download. There is no need for packet segmentation in RNC. By introducing the segmentation to the MAC, the MAC can perform the segmentation of the large RLC PDU based on physical layer requirements when needed. The fl exible RLC concept in downlink is illustrated in Figure above.


There is a lot of interesting information in R&S presentation on HSPA. See here.

Main source of the content above and for further information see: LTE for UMTS: OFDMA and SC-FDMA Based Radio Access

TD-SCDMA, TDD and FDD

After my posting on TD-SCDMA so many people asked me about what TD-SCDMA is. I am surprised that so many people are not aware of TD-SCDMA. So here is a quick posting on that.

TDD and FDD Mode of Operation

Basically most of the UMTS networks in operation are Frequency Division Duplex (FDD) based. There is also another variant called the Time Division Duplex or TDD. In reality there is more than one variant of TDD, so the normal 5MHz bandwidth TDD is called Wideband TDD of WTDD. There is also another name for WTDD to confuse people, called the High Chip Rate TDD (HCR-TDD). There is another variant of TDD as would have guessed known as the Narrowband TDD (NTDD). NTDD is also known as Low Chip Rate TDD (LCR-TDD) and most popularly its known as TD-SCDMA or Time Division Synchronous CDMA.

"Synchronous" implies that uplink signals are synchronized at the base station receiver, achieved by continuous timing adjustments. This reduces the interference between users of the same timeslot using different codes by improving the orthogonality between the codes, therefore increasing system capacity, at the cost of some hardware complexity in achieving uplink synchronization.

The normal bandwidth of FDD or TDD mode of operation is 5 MHz. This gives a chip rate of 3.84 Mcps (Mega chips per second). The corresponding figure for TD-SCDMA is 1.66 Mhz and 1.28 Mcps.

Assymetric operation in TDD mode

The advantage of TDD over FDD are:

• Does not require paired spectrum because FDD uses different frequencies for UL and DL whereas TDD uses the same frequency hence its more easy to deploy
• Channel charachteristics is the same in both directions due to same band
• You can dynamically change the UL and the DL bandwidth allocation depending on the traffic.
  

The dis-advantage of TDD over FDD are:

• Switching between transmission directions requires time, and the switching transients must be controlled. To avoid corrupted transmission, the uplink and downlink transmissions require a common means of agreeing on transmission direction and allowed time to transmit. Corruption of transmission is avoided by allocating a guard period which allows uncorrupted propagation to counter the propagation delay. Discontinuous transmission may also cause audible interference to audio equipment that does not comply with electromagnetic susceptibility requirements.
• Base stations need to be synchronised with respect to the uplink and downlink transmission times. If neighbouring base stations use different uplink and downlink assignments and share the same channel, then interference may occur between cells. This can increase the complexity of the system and the cost.
• Also it does not support soft/softer handovers

Timing Synchronisation between different terminals

By the way, in Release 7 a new TDD mode of operation with 10 MHz bandwidth (7.86 Mcps) has been added. Unfortunately I dont know much about it.

You can read more about TD-SCDMA in whitepaper 'TD-SCDMA: the Solution for TDD bands'

You can find more information on TD-SCDMA at: http://www.td-forum.org/en/

HSPA+ is everywhere...

EMobile Ltd. , Japan's smallest mobile operator, has deployed HSPA+, also known as HSPA Evolved, in the country's major cities, including Tokyo, Osaka, Yokohama, and Nagoya.

This deployment is based on equipment from Ericsson AB, which supplied the core network and core systems integration services as well as the majority of the radio access network. It builds out the geographical coverage for HSPA+ that EMobile has already established using Huawei Technologies Co. Ltd. equipment in a number of Japan's other cities, including Hokkaido, Sendai, Niigata, Hiroshima, Fukuoka, and Nagasaki.

Japan is a market with a reputation for being first with new technology, but HSPA+ has been passed over, most notably by market leader NTT DoCoMo Inc., which has focused on moving to Long-Term Evolution (LTE) as fast as possible.

The No. 2 player, KDDI Corp. , is similarly pushing toward LTE, although from a CDMA base that takes HSPA out of the equation, while Softbank Mobile Corp. is known to have run HSPA+ lab trials and has also said it will move to LTE when it gets the necessary spectrum.

EMobile is by far the smallest of Japan's operators, with just 1.67 million subscribers at the end of the second quarter, compared to DoCoMo's 54.86 million, KDDI's 31 million, and Softbank's 20.96 million customers, according to Wireless Intelligence .

You can check out the HSPA+ features in Rel-7 and Rel-8 here.

Zapp, mobile operator of Romania, has launched the first stage of its HSPA+, the upgraded mobile broadband service in the capital city of Bucharest. With this service, the subscribers can enjoy peak download speeds of 21.6Mbps, while upload speeds will increase by up to 15 times, from 384Kbps to 5.8Mbps. According to a report, Zapp contracted Chinese firm ZTE to deploy the network, which will run parallel to the cellco’s second phase 3G rollout, expanding its UMTS services to 63 cities nationwide.


O2 Germany is currently running a friendly user test in Munich where O2 Germany's technology partner is Huawei. Beside being O2's network partner for the overall HSPA-network upgrade, Huawei is also O2 Germany's major vendor for UMTS sticks and therefore O2 Germany is using Huawei equipment for the HSPA+ test as well. The used Huawei E182E stick is a slide-out USB stick, supporting quadband GSM/GPRS/EDGE as well as quadband UMTS/HSDPA up to 21.6 Mbps and HSUPA up to 5.76 Mbps. Furthermore the stick is MIMO ready.

Spanish mobile network operator Vodafone Spain has announced it will begin deploying HSPA+ technology across its network in the autumn of 2009. The cellco says the upgrade will allow its infrastructure to achieve theoretical download speeds of up to 21.6Mbps, while uplink speeds would increase to up to 5.7Mbps. Initially Vodafone expects to launch the increased speeds in seven unnamed ‘major’ cities, with further expansion to follow. In addition, Francisco Roman, president and CEO of Vodafone Spain, has announced that the operator plans to further extend its provision of ADSL services across the country, although it has not given any specifics for areas it plans to extend its reach to.

­Swiss network operator, Swisscom says that it is deploying a HSPA+ (HSPA Evolution) upgrade, with the first areas completed in time for the ITU Telecom World 2009 in Geneva. The upgrade will offer a peak rate data transfer rate of 28.8 Mbps - although the more realistic average is no higher than 8Mbps. The network has launched a HSPA 14.4Mbps service at the beginning of this year.

Chunghwa Telecom, the Taiwanese mobile operator has reportedly selected Nokia Siemens Networks (NSN) to upgrade its wireless infrastructure with HSPA+ technology. The operator intends to launch its HSPA+ and 3G services by 2010, boosting mobile broadband download speeds to up to 21Mbps. Initially, devices able to utilise the HSPA+ service will include data network cards, USB dongles and wireless modules before it is extended to cover smartphones, netbooks and notebooks.

ZTE Corp has completed the interoperability test (IOT) of its 3GPP R7-based HSPA+ MIMO (multiple-input multiple-output) solution, conducted in conjunction with mainstream terminal chip platform manufacturers, in July 2009.

The MIMO solution, realized with its SDR-based next-generation base station, has reached a theoretical speed limit of 28.8Mbps in both cable connection and wireless environment tests. The trials included data download services for UDP (User Datagram Protocol) and FTP (File Transfer Protocol), as well as various IOT item tests.

All the test results indicated stable and fast data download performance. The successful IOT testing confirms that ZTE's MIMO solution is now ready for large-scale commercial deployment worldwide.

HSPA+ to become more widely available in 2009

According to 3G Americas press release, 100 million new connections were added last year. On a worldwide basis, GSM totals 3.5 billion of the nearly 4 billion mobile subscriptions or 89% share of market at the end of December 2008. With 278 UMTS-HSPA networks in service in 121 countries, there are 290 million UMTS-HSPA subscriptions as of the end of 2008 compared to 186 million a year earlier—more than 100 million new 3G connections. UMTS-HSPA subscriptions are expected to more than double in 2009, according to Informa’s forecasts, and reach 455 million connections by the end of this year.

A survey last year by GSA showed that over 1000 HSPA devices have already been launched. Remember HSPA device could be HSDPA device only or HSDPA and HSUPA device. According to Dell'Oro group, Worldwide total mobile infrastructure market revenues grew 5% in 2008, driven by the nearly doubling and quadrupling of revenues of the WCDMA and WiMAX markets, respectively.

The focus is now moving towards HSPA+ (Release 7). HSPA+ is already becoming everyones favourite as it now has the potential to compete with LTE. The HSPA+ data rates will soon be able to rival that of LTE. No new spectrum will be required and enhancements will now allow multiple bands to be used at the same time thereby reducing the need to move to LTE for gaining higher data rates by use of higher bandwidth.

O2 Germany is planning to upgrade its network to HSPA+ by mid 2009. Vodafone also plans to upgrade its network to HSPA+ when more devices are available. Hong Kong operator CSLNWM is working with China's ZTE to upgrade their network to SDR based HSPA+ network that could easily be upgraded to LTE. Australia's Telstra has already announced at the Mobile World Congress in Barcelona that it is the first in the world to offer mobile broadband service with peak rates of 21 Mbps made possible through HSPA+ technology.

On the devices front Huawei has E182E HSPA+ slide USB stick supporting 21.6Mbps DL and 5.76Mbps in UL. Novatel surprisingly has the same specs for its MC996D modem. Qualcomm meanwhile has released a range of new HSPA+ capable chipsets. The MSM8260 supports 3GPP Release 7 HSPA+ for data rates of up to 28 Mbps. The MSM8660 adds support for 3GPP/3GPP2 multimode, and the MSM8270 adds support for Release 8 dual-carrier HSPA+ for even higher data rates of up to 42 Mbps. All three products offer full backward compatibility to previous generation networks and are pin-, software- and functionally-compatible.

Its just a matter of time before we will all be able to experience the HSPA+ speeds on our mobiles and mobile connected Laptops.

HSPA+ arriving soon from Vodafone and TIM

Telecom Italia Mobile (TIM) says it will be offering mobile data packages with peak download speeds of 21Mbps by mid-2009, rising to 28Mbps by year-end. The services, based on HSPA+ technology, will initially work via PC datacards using Qualcomm chipsets, CellularNews reports. Ericsson will supply equipment for the network upgrade.

Vodafone has trialled the Release 7 version HSPA+ mobile broadband technology in its Spanish network, and has achieved actual peak data download rates of up to 16Mbits/s.

The field trail of the HSPA+ 64QAM technology was done in conjunction with chip supplier Qualcomm Inc. and network gear provider Ericsson, following convincing results in laboratory tests.

Vodafone now plans to trial mobile broadband data connections with peak rates of up to 21Mbits/s early in 2009 using HSPA+ MIMO functionality.

The operator says the technology would be capable of video downloads at more than 13Mbits/s in good conditions and an average of more than 4 Mbits/s across a full range of typical cell locations, including urban environments.

If the trials prove a success, Vodafone plans to make this technology available in selected commercial networks.

HSPA+ technology is the next evolutionary step in the (3G) HSPA roadmap and increases performance through the use of the more powerful 64QAM modulation technique. Download performance is also improved through the use of multiple antennae (MIMO) technology on both base stations and data devices.

The operator is also working with several device vendors on the testing and validation of these devices ready for commercial availability.

Other major operators known to be conducting trials of HSPA+ technology include 3 and Australian company Telstra.

Telecoms equipment supplier Huawei has revealed that it will be showing off the world’s first commercial HSPA+ modem at the upcoming Mobile World Congress event, taking place in Barcelona next month.

Huawei’s connection to the Vodafone trials is unknown, but The Link has done a bit of detective work and observes that Vodafone released a statement early last year announcing partnerships with Huawei (amongst others) to develop the service. Huawei’s commercial HSPA+ stick could therefore be the first glance of Vodafone’s upcoming service, unless of course another network has quietly beaten it to the punch.

No release date or price has been revealed, but it does sound like HSPA+ will be arriving a lot sooner than we’d first thought. Mobile World Congress is taking place from the 16th – 19th February.

Updated Paper on 3GPP Rel 7 and Rel 8 from 3G Americas

3G Americas, a wireless industry group supporting the GSM family of technologies in the Americas, has provided updates to its popular white paper titled UMTS Evolution from 3GPP Release 7 to Release 8: HSPA and SAE/LTE that explains the leading evolutionary roadmap for the GSM family of technologies to 3G and beyond. Globally, the demand for wireless data services is driving the growth of 3G UMTS/HSPA technology with more than 200 commercial HSDPA networks today and subscriptions to UMTS/HSPA estimated at over 236 million by Informa Telecoms and Media. With more than 3.1 billion subscriptions for the GSM family of technologies worldwide today, the potential for third generation HSPA technology is forecast to reach 1.39 billion subscriptions by year end 2012 and 1.8 billion by year end 2013 according to Informa.

UMTS Evolution from 3GPP Release 7 to Release 8: HSPA and SAE/LTE offers a further review of 3GPP Release-7 (Rel-7) upon its completion in the technology standardization process and an introduction to the improved features of 3GPP Release 8 (Rel-8). The paper explores the growing demands for wireless data and successes for a variety of wireless applications, the increasing Average Revenue per User (ARPU) for wireless services by operators worldwide, recent developments in 3GPP technologies by several leading manufacturers, and 3GPP technology benefits and technical features.

Upon the finalization of the Rel-8 standard later this year, 3G Americas will publish a new white paper on the 3GPP standards that will include the completion of Rel-7 HSPA+ features, voice over HSPA, SAE/EPC (Evolved Packet Core) specification and Common IMS among other new developments and features. Since HSPA+ enhancements are fully backwards compatible with Rel-99/Rel-5/Rel-6, the upgrade to HSPA+ has been made smooth and evolutionary for GSM operators. Additionally, Rel-7 standardizes Evolved EDGE with continuing development in Rel-8 which will improve the user experience across all wireless data services by reducing latency and increasing data throughput and capacity. Finalization of the Rel-8 standard by the end of this year will further progress market interest in commercial deployment of LTE. Leading operators worldwide are announcing their plans to deploy LTE as early as 2010 with trials already occurring today.

The popular white paper UMTS Evolution from 3GPP Release 7 to Release 8: HSPA and SAE/LTE was written collaboratively by members of 3G Americas and is available for free download here.

Flatter Architecture from Nokia-Siemens Network

From Unstrung:

In its bid to overtake Ericsson AB and become the world’s top radio access infrastructure supplier in terms of revenue, Nokia Siemens Networks believes its approach to all-IP flat architecture on 3G networks will give it an edge. Nokia Siemens says operators do not have to wait for LTE, to get the benefits of an all-IP architecture, and it is the only vendor that currently champions a flat 3G radio access network (RAN) approach.

As mobile data traffic continues to surge, operators are considering how to adopt flat, all-IP architectures in their 3G networks before the advent of 4G in order to gain lower latency, lower cost per bit, support for multiple access networks, and preparation for next-generation networks. But there are different ways to implement such architectures, and just how operators arrive at a flatter data network architecture is hotly debated.

Nokia Siemens has put its money on a flat RAN approach for high-speed packet access (HSPA) and the coming HSPA+ standard, in addition to its support for the Direct Tunnel architecture.
In a flat RAN architecture, the radio network controller (RNC) is integrated into the Node B so that the base station communicates directly with the Gateway GPRS Support Node (GGSN).
But there are as many benefits as drawbacks to flat 3G RANs, which makes it a controversial approach, according to the recent Heavy Reading report, "Flat IP Architectures in Mobile Networks: From 3G to LTE."

With flat RANs, some of the benefits include lower latency for data applications, lower operational costs due to fewer nodes to maintain and manage, augmented data capacity through a data network overlay, and good preparation for so-called 4G LTE/SAE (System Architecture Evolution), which uses a similar functional architecture. Also, costs won’t grow in line with data traffic growth, because operators won’t have to deploy extra RNC and SGSN capacity as traffic increases.

It may be challenging to integrate the RNC into a Node B. RNCs are critical to supporting macro-diversity in mobile networks, which enables mobile handsets to communicate with multiple base stations on the uplink and allows operators to deploy fewer base stations. NSN’s flat RAN architecture supports this feature, but in an unorthodox way, according to the Heavy Reading report.

So far, Nokia Siemens has three customers using its Internet HSPA (I-HSPA) flat RAN solution: Stelera Wireless and TerreStar Neworks in the U.S. and T-2 in Slovenia. And Mobilkom Austria AG & Co. KG recently trialed the solution.

Nokia Siemens’ Rouanne explains that flat 3G RANs aren’t necessary when there is just “medium” data traffic, but are best suited when operators have big data traffic volumes. “Those networks that are starting to be under pressure with traffic are coming to us and wanting to direct traffic directly to the Internet,” he says.

Even though Nokia Siemens is the only vocal supporter of flat 3G RANs right now, Brown says the strategy isn’t risky, but it’s “forward-looking.”

And a flat 3G RAN can set up an operator to be ready for the shift to LTE with its inherent flat architecture.

According to an old Ericsson presentation, ”Direct Tunnel” support added for 3G payload optimization has the following advantages:

• Cost efficient scaling for Mobile Broadband deployments
• Increased flexibility in terms of network topology
• Allows the SGSN node to be optimized for control plane
• Specifications part of 3GPP rel-7
• Designed for operation in legacy (GGSN/UTRAN) networks
• First step towards the SAE architecture

According to heavy reading article:

To efficiently deliver mobile broadband services, operators require a network infrastructure that simultaneously provides lower costs, lower latency, and greater flexibility. The key to achieving this goal is the adoption of flat, all-IP network architectures. With the shift to flat IP architectures, mobile operators can:

• Reduce the number of network elements in the data path to lower operations costs and capital expenditure
• Partially decouple the cost of delivering service from the volume of data transmitted to align infrastructure capabilities with emerging application requirements
• Minimize system latency and enable applications with a lower tolerance for delay; upcoming latency enhancements on the radio link can also be fully realized
• Evolve radio access and packet core networks independently of each other to a greater extent than in the past, creating greater flexibility in network planning and deployment
• Develop a flexible core network that can serve as the basis for service innovation across both mobile and generic IP access networks
• Create a platform that will enable mobile broadband operators to be competitive, from a price/performance perspective, with wired networks

Note: Diagrams above shamelessly copied from Ericsson's presentation.

All about F-DPCH

Fractional DPCH was added in Rel-6 to optimise the consumption of downlink channelization codes. When using HS-DSCH (High Speed Downlink Shared Channel), the main use for DL DPCH (also known as A-DPCH where A stands for Associated) is to carry power control commands (TPC bits) to the UE in order to adjust the uplink transmission. If all RBs (Radio Bearers) including SRBs (Signalling Radio Bearers) are mapped on to HS-DSCH then the DL codes are being wasted. SF 256 is used for A-DPCH and so every code being used by a user is seriously depleting the codes available for other UE's. To overcome this F-DPCH is used so that multiple UE's can share a single DL channelisation code. The limitation is 10 UEs in Rel-6.

For several users, the network configures each user having the same code but different frame timing and, thus, users can be transmitted on the single code source. The original timing is thus retained which avoids the need to adjust timings based on Release 99 power control loop implementation.

During slots where the DPCCH is not transmitted, the NodeB cannot estimate the uplink signal-to-interference ratio for power-control purposes and there is no reason for transmitting a power control bit in the downlink. Consequently, the UE shall not receive any power control commands on the F-DPCH in downlink slots corresponding to inactive uplink DPCCH slots.

There are some restrictions for FDPCH. It is not usable with services requiring data to be mapped to the DCH, such as AMR speech calls and CS video. Also, the lack of pilot information means that a method like feedback-based transmit diversity (closed loop mode) is not usable. The use of closed loop diversity is based on user-specific phase modification, wherein pilot symbols would be needed for verification of the phase rotation applied. On the other hand, when utilizing the F-DPCH, SRBs can benefit from high data rates of HSDPA and reduce service setup times remarkably

Finally, as you may have already figured out, by using F-DPCH the cell capacity has been improved and at the same time for same number of users, the interference has gone down significantly.

In Release 7, Rel-6 limitation has been removed. In R6, for a given UE in soft handover the TPC from all F-DPCH had to have the same offset timing. In R7, F-DPCH (TPC bits) can have different timing from different cells. This is possible due to introduction of 9 new F-DPCH slot formats (slot format 0 is the legacy F-DPCH slot format). The RRC signalling is done seperately for slot formats from the RNC to each of the cells.

You may also be interested in this Ericsson paper titled "The effect of F-DPCH on VoIP over HSDPA Capacity". Available here.

HSPA+ in Release-7 and Release-8

Thought of adding this while I am in mode of making lists. So whats in HSPA evolution in Rel-7 and Rel-8. Lot of people are unaware that HSPA+ was big enough to finish off in Rel-7 and was definite to spill over in Rel-8

HSPA+ Features in Release 7

• Higher Order Modulation Schemes
  


• Advantages and weaknesses of higher order modulation
  - Interference Sensitivity
  - QPSK
  - 16-QAM, 64-QAM)
  - Consequences
  - Behavior in Time Variant Mobile Radio Channels
  - Behavior of a time variant mobile radio channel
  - Effect of amplitude variations
  - Effect of phase variations


• 16-QAM for the S-CCPCH (DL)
  - MBSFN only
  - Interleaving
  - Modulation
  - Scaling factors


• 64-QAM for the HS-PDSCH (DL)
  - Interleaving
  - Constellation Rearrangement
  - Modulation
  - Related UE Categories


• 16-QAM for UL (4-PAM for the E-DPDCH)
  - HARQ Rate Matching Stage
  - Interleaver
  - Modulator
  - UE category


• Overview Advantages and Disadvantages
  - Higher peak data rate
  - Better resource utilization
  - Blind choice of modulation scheme
  - High SNIR requirement
  - More TX power requirement
  - Low range
  - Small cell environment
  - Restrictions of use for high UE moving speeds


• Channel Estimation Algorithms
  - Normal Algorithm
  - Gathering pilot information
  - Channel estimation
  - Data detection
  - Advantage
  - Disadvantage
  - Advanced Algorithms
  - Shorter channel estimation window
  - Moving channel estimation window
  - Adaptive detection
  - Turbo detection
  - Advantages
  - Disadvantages


• Performance16-QAM in the UL
  - Performance on Link Level 16-QAM in the UL
  - Performance of BPSK compared to 4-PAM
  - Influence of non-linearity of the power amplifier
  - Performance on System Level
  - Behavior with increasing load
  - Maximum versus average throughput


• Higher Order Modulation Testing
  - Test Setup for 16-QAM in the UL
  - RF components
  - Discussion of the setup
  - Selected Performance Requirements for 16-QAM in the UL
  - BPSK vs. 4-PAM
  - Effect of RX diversity
  - Effect of high degree of multipath
  - Effect of high UE moving speed


• MIMO
  


• Introduction to MIMO Technology
  - The Basics: Signal Fading Physics between TX and RX
  - Scattering
  - Refraction
  - Reflection
  - Diffraction
  - Multiplexing Dimensions
  - The Multipath Dimension
  - MIMO General Operation


• MIMO Feedback Procedure (PCI)
  - Motivation of Spatial Precoding
  - Plain MIMO
  - Multiple rank beamforming
  - Spatial Precoding
  - Codebook, PCI and CQI Loop
  - Codebook
  - PCI and CQI loop


• MIMO Algorithms
  - Linear MIMO Algorithms (Preparation work, Equalizer at the end of the processing chain,
  - Equalizer at the beginning of the processing chain), Non-Linear MIMO Algorithms


• MIMO Performance
  - MIMO Performance on Link Level (SISO vs. SIMO, SIMO vs. MIMO, 2x2 MIMO vs. 4x2
  - MIMO, 16-QAM vs. 64-QAM), Performance on System Level (MIMO vs. SIMO, 50% vs.
  - 75% power allocation, 0% vs. 4% feedback errors)


• MIMO Tests
  - Official Test Setups (Test NodeB, Fading simulator, Noise generator, UE under test, Single stream test setup, Double stream test setup), Quick and Easy Test Setups (The
  easiest test setup, A more reliable test setup: The MIMO circle), Selected Performance
  - Requirement Figures (Conditions, 64-QAM performance, Dual stream MIMO
  performance, Single stream MIMO performance)


• Continuous Packet Connectivity (CPC)
  


• Basic features
  - Uplink Discontinuous Transmission (DTX), Downlink Discontinuous Reception (DRX)


• RRC message ID’s
  - DTX and DRX Information


• CPC Timing
  - Uplink CQI transmission


• Example for Uplink DPCCH Burst Pattern for 10 ms E-DCH TTI
  - Uplink DRX, Downlink DRX


• Uplink DPCCH preamble and postamble
  - Uplink DPCCH preamble and postamble for the DPCCH only transmission, Uplink DPCCH preamble and postamble for the E-DCH transmission, Uplink DPCCH preamble and postamble for the HS-DPCCH transmission


• Example of simultaneous Uplink DTX and Downlink DRX


• CPC and Enhanced F-DPCH
  - Timing Implications for CPC + Enhanced F-DPCCH


• Upgraded L1 Signaling
  


• HS-SCCH Review of Rel. 5 and 6
  - HS-SCCH Frame Structure, HS-SCCH Part 1 and 2 Forward Error Coding Chain, UE
  specific masking of Part 1 and Part 2, HS-PDSCH Code Allocation through Part1 of HSSCCH,
  - Transport Block Size Determination – TFRI Mapping


• HS-SCCH of Rel. 7
  - HS-SCCH Overview of Rel. 7 (HS-SCCH type 1, No HS-SCCH, HS-SCCH type 2, HSSCCH
  type 3), HS-SCCH Type 1 (HS-SCCH Type 1, HS-SCCH Type 1 for Configured 64-QAM Operation, HS-SCCH Orders, 64-QAM Constellation Versions), HS-SCCH Type 2 (for HS-SCCH less operation) (Use of the HS-SCCH-less operation, Procedure HSSCCH-less operation), HS-SCCH Type 3 (HS-SCCH Type 3 Overview, Modulation and
  Transport Block Number , HARQ Process Number, Redundancy Version and
  Constellation Version)


• HS-DPCCH of Rel. 7
  - HS-DPCCH ACK/NACK (ACK-NACK of primary TB in R5, Preamble and postamble in
  R6, ACK-NACK of 2 TB’s in R7), HS-DPCCH PCI and CQI type A and B (CQI in case of
  no MIMO operation, PCI and CQI in case of MIMO with 1 TB (CQI type A), PCI and CQI
  in case of MIMO with 2 TB’s (CQI type B))


• E-AGCH and E-DPCCH
  - Changes in the E-TFCI tables, Changes in the AG tables, Changes in the SG tables


• MAC-ehs Entity versus MAC-hs
  


• UTRAN side MAC-hs Details – CELL_DCH only
  - Flow Control, Scheduling/Priority Handling, HARQ, TFRC selection


• UE side MAC-hs Details – CELL_DCH only
  - HARQ, Reordering Queue distribution, Reordering, Disassembly


• UTRAN side MAC-ehs Details
  - Some advantages of MAC-ehs compared to MAC-hs , Flow Control, HARQ, TFRC
  selection (~ TFRI), LCH-ID mux, Segmentation


• UE side MAC-ehs Details
  - HARQ , Disassembly, Reordering queue distribution, Reordering, Reassembly, LCH-ID demultiplexing


• Differences in the MAC-ehs and MAC-hs Header
  - MAC-hs Header Parameter Description
  - MAC-hs SDU , , MAC-hs Header of MAC-hs PDU), MAC-ehs Header Parameter Description
  - MAC-ehs Header Parameter Details
  - HARQ Process Work Flow in UE – MAC-hs / MAC-ehs
  - Split HS-DSCH Block Functionality
  - Practical Exercise: MAC-hs contra MAC-ehs
  - MAC-hs / MAC-ehs Stall Avoidance
  - Timer-Based Scheme
  - Window Bases Scheme
  - MAC-(e)hs Reordering Functionality – Timer / Window based


• Flexible RLC PDU Sizes
  


• The RLC AMD PDU – Rel. 7 Enhancements
  - The Poll (POLL) super-field
  - RLC AMD Header Fields
  - Release 7 Enhancement of the HE-Field and LI


• Comparison of RLC-AM between Rel. 6 and Rel. 7
  - RLC-AM Overhead using fixed or flexible PDU size
  · RRC State Operation Enhancements


• Transport Channel Type Switching with HSPA in R6
  - Transport Channel Combinations between UL and DL, Radio Bearer Multiplexing Options in Rel. 6


• Operation of UTRA RRC States in Release 7
  - UE Idle mode, CELL_DCH state


• HS-DSCH Reception in CELL_FACH and XXX_PCH
  - Overview (UE dedicated paging in CELL_DCH, CELL_FACH and CELL_PCH, BCCH
  reception in CELL_FACH, FACH measurement occasion calculation, Measurement
  reporting procedure), (1) Operation in the CELL_FACH state (DCCH / DTCH reception in
  CELL_FACH state , User data on HS-DSCH in Enhanced CELL_FACH state), (2) Operation in the CELL_FACH state – Cell Update, (3) RRC Idle to transient CELL_FACH
  (Common H-RNTI selection in CELL_FACH (FDD only), H-RNTI selection when entering
  Connected mode (FDD only) ), Operation in the URA_PCH or CELL_PCH state (Data
  Transfer in CELL_PCH with dH-RNTI, State Transision from CELL_PCH to CELL_FACH
  to CELL_DCH, CELL_PCH and URA_PCH enhanced Paging Procedure)
  

HSPA+ Features in Release 8

• Overview of HSPA+ Related Work Items in R8
  


• Requirements for two branch IC


• CS voice over HSPA


• Performance req. for 15 HSDPA codes


• MIMO + 64-QAM


• Enhanced DRX


• Improved L2 for UL


• Enhanced UL for CELL_FACH


• R3 Enhancements for HSPA


• Enhanced SRNS relocation


• MIMO combined with 64-QAM
  


• New UE Categories
  - Data Rate, Soft IR memory


• L1 Signaling of MIMO and 64-QAM
  - Modulation Schemes and TB Sizes (Signaling on the HS-SCCH type 3, Dilemma to signal
  on the modulation schema and TB number field, Solution), CQI Signaling, CQI Tables
  used

Interested readers can refer to Alcatel-Lucent presentation in HSPA+ Summit here.

There is also an interesting Qualcomm paper titled, "Release 7 HSPA+ For Mobile Broadband Evolution" available here.

Security Upgrade from Release 7

For those familiar with the 3G Security (Ciphering + Integrity) architecture will know this well that there is only one Integrity algorithm (UIA1) defined and it is mandatory. On the other hand there are two ciphering algorithms (UEA0 and UEA1) defined. UEA0 in reality means no Ciphering ;). UIA1 and UEA1 are both based on Kasumi algorithm. UEA1 is f8 and UIA1 is f9 algorithms of Kasumi. (Please feel free to correct my terminology if you think its wrong).

From Release 7 there are some additional provisions made for increasing the security.

First lets talk about GSM. Initially only a5_1 and a5_2 algorithms were defined for GSM. They have not been compromised till date and are still secure. Still some new algorithms have been defined to make sure there is a backup if they are ever compromised. a5_3, a5_5 and a5_8 have been defined for GSM/GPRS and GEA3 defined for EDGE.

For UMTS, UEA2 and UIA2 have been defined. They are based on 'Snow 3G' algorithm. Kasumi is a 'blockcipher' algorithm whereas Snow 3G is 'streamcipher'. The interesting thing as far as I understand is that even though this is defined and mandatory for UEs and N/w from Rel7, it wont be used but will only serve as backup. More on this topic can be learnt here.

More detailed information on UIA2 and UEA2 is available here.

There are some enhancements coming in the SIM as well. At present all the Keys are 128bits but there should be a provision that in future, 256 bits can be used.

There are some extensive overhauling of IMS security as well but I havent managed to get a good understanding of that yet.

All the reports from the 3rd ETSI Security Workshop held on Jan 15-16 2008 are available here.

SFN for MBMS in Release 7

MBMS in Release 6, can combine signals from different cells and this can be used to boost the reliability of the received signal. Though this concept is good, the other neighbouring cells are still causing interference since the adjacent cells are not orthogonal due to different scrambling codes. If the same scrambling code were to be used in all cells and the cells were to be synchronised, the other cells’ interference would turn into multipath
propagation. The received signal looks as if there is only a single base station transmitting, but with more multipath components. Therefore, this approach is called an SFN (Single Frequency Network).

Similar approach is also used in other Mobile-TV technologies like DVB-H.

The SFN approach is available in Release 7 and can be implemented with relatively minor modifications to the radio network while providing a major gain in the broadcast data rates. On the other hand, SFN transmission requires that the whole 5 MHz carrier is allocated for MBMS usage only, which requires that the total amount of spectrum for the operator is large enough.

Source: WCDMA for UMTS – HSPA Evolution and LTE, fourth edition. Edited by Harri Holma and Antti Toskala, John Wiley & Sons, Ltd.