Showing posts with label HSPA. Show all posts
Showing posts with label HSPA. Show all posts

Saturday, 15 March 2014

HSPA+ Carrier Aggregation

Came across Qualcomm's HSPA+ Carrier aggregation video (above) and whitepaper. Interesting to see that HSPA/HSPA+ is still growing. As per my earlier post, half of the connections in 2018 would be HSPA/HSPA+.

As can be seen in the picture above, there are quite a few features that may be of interest to the operators. Scalable UMTS is one such feature as I have put in the blog before.

You will notice that upto 4 bands can be aggregated. It would be interesting to see which operators have these bands available and if they would be willing to use HSPA+ CA with upto 4 bands. The presentation by Qualcomm is embedded below and is available to download from here.

Related posts:

Tuesday, 18 February 2014

The Rise and Rise or '4G' - Update on Release-11 & Release-12 features

A recent GSMA report suggests that China will be a significant player in the field of 4G with upto 900 million 4G users by 2020. This is not surprising as the largest operator, China Mobile wants to desperately move its user base to 4G. For 3G it was stuck with TD-SCDMA or the TDD LCR option. This 3G technology is not as good as its FDD variant, commonly known as UMTS.

This trend of migrating to 4G is not unique to China. A recent report (embedded below) by 4G Americas predicts that by the end of 2018, HSPA/HSPA+ would be the most popular technology whereas LTE would be making an impact with 1.3 Billion connected devices. The main reason for HSPA being so dominant is due to the fact that HSPA devices are mature and are available now. LTE devices, even though available are still slightly expensive. At the same time, operators are taking time having a seamless 4G coverage throughout the region. My guess would be that the number of devices that are 4G ready would be much higher than 1.3 Billion.

It is interesting to see that the number of 'Non-Smartphones' remain constant but at the same time, their share is going down. It would be useful to breakdown the number of Smartphones into 'Phablets' and 'non-Phablets' category.

Anyway, the 4G Americas report from which the information above is extracted contains lots of interesting details about Release-11 and Release-12 HSPA+ and LTE. The only problem I found is that its too long for most people to go through completely.

The whitepaper contains the following information:

3GPP Rel-11 standards for HSPA+ and LTE-Advanced were frozen in December 2012 with the core network protocols stable in December 2012 and Radio Access Network (RAN) protocols stable in March 2013. Key features detailed in the paper for Rel-11 include:
  • 8-carrier downlink operation (HSDPA)
  • Downlink (DL) 4-branch Multiple Input Multiple Output (MIMO) antennas
  • DL Multi-Flow Transmission
  • Uplink (UL) dual antenna beamforming (both closed and open loop transmit diversity)
  • UL MIMO with 64 Quadrature Amplitude Modulation (64-QAM)
  • Several CELL_FACH (Forward Access Channel) state enhancements (for smartphone type traffic) and non-contiguous HSDPA Carrier Aggregation (CA)
  • Carrier Aggregation (CA)
  • Multimedia Broadcast Multicast Services (MBMS) and Self Organizing Networks (SON)
  • Introduction to the Coordinated Multi-Point (CoMP) feature for enabling coordinated scheduling and/or beamforming
  • Enhanced Physical Control Channel (EPDCCH)
  • Further enhanced Inter-Cell Interference Coordination (FeICIC) for devices with interference cancellation
Finally, Rel-11 introduces several network and service related enhancements (most of which apply to both HSPA and LTE):
  • Machine Type Communications (MTC)
  • IP Multimedia Systems (IMS)
  • Wi-Fi integration
  • Home NodeB (HNB) and Home e-NodeB (HeNB)
3GPP started work on Rel-12 in December 2012 and an 18-month timeframe for completion was planned. The work continues into 2014 and areas that are still incomplete are carefully noted in the report.  Work will be ratified by June 2014 with the exception of RAN protocols which will be finalized by September 2014. Key features detailed in the paper for Rel-12 include:
  • Universal Mobile Telecommunication System (UMTS) Heterogeneous Networks (HetNet)
  • Scalable UMTS Frequency Division Duplex (FDD) bandwidth
  • Enhanced Uplink (EUL) enhancements
  • Emergency warning for Universal Terrestrial Radio Access Network (UTRAN)
  • HNB mobility
  • HNB positioning for Universal Terrestrial Radio Access (UTRA)
  • Machine Type Communications (MTC)
  • Dedicated Channel (DCH) enhancements
  • Active Antenna Systems (AAS)
  • Downlink enhancements for MIMO antenna systems
  • Small cell and femtocell enhancements
  • Machine Type Communication (MTC)
  • Proximity Service (ProSe)
  • User Equipment (UE)
  • Self-Optimizing Networks (SON)
  • Heterogeneous Network (HetNet) mobility
  • Multimedia Broadcast/Multicast Services (MBMS)
  • Local Internet Protocol Access/Selected Internet Protocol Traffic Offload (LIPA/SIPTO)
  • Enhanced International Mobile Telecommunications Advanced (eIMTA) and Frequency Division Duplex-Time Division Duplex Carrier Aggregation (FDD-TDD CA)
Work in Rel-12 also included features for network and services enhancements for MTC, public safety and Wi-Fi integration, system capacity and stability, Web Real-Time Communication (WebRTC), further network energy savings, multimedia and Policy and Charging Control (PCC) framework.

Thursday, 5 September 2013

Throughput Comparison for different wireless technologies

Merged various slides from the recent 4G Americas presentation to get a complete picture of data throughput speeds for various technologies.

Thursday, 14 February 2013

Scalable UMTS (S-UMTS) to accelerate GSM Refarming

Looks like a good idea from LTE will possibly be applied to UMTS/HSPA and it will also help accelerate the re-farming of GSM spectrum. A recent presentation from Qualcomm below:

Available to download from here.

Thursday, 7 June 2012

On Signalling Storm... #LTEWS

The Signalling Storm is coming, its not the question of 'if' but when. This was the unanimous message from the Signaling Focus Day of the 8th LTE World Summit 2012. Several high profile outages have been associated to the Signalling storm, NTT Docomo and Verizon being the main one. Luckily the Telenor outage was due to software issues.

The problem is divided into two parts, the Access network part where the Air Interface is the bottleneck and the core network part which can easily be swamped by the overwhelming amount of Signalling due to more intelligent billing system and always on devices with background applications generating much more amount of traffic as would have on an older system. Lets look at them in turn.

Core Network Signalling Storm:

As I reported earlier, Diameter has been highlighted as a way of salvation for the operators with dozens of use cases but due to its immaturity has caused outages and have given it a bad name. As Connected Planet mentions, "According to one signaling expert, launching the iPhone’s browser, for example, instantly sets off about fifteen individual network signaling requests. Beyond that, 4G network software elements supporting increasingly sophisticated mobile service scenarios “talk” to each other at rates that traditional TDM/SS7-based networks never had to deal with." Hopefully a stable implementation of Diameter protocol will help not only solve the signalling storm but will help generate new models for charging and revenue generation.

A presentation by Ed Gubbins of Current Analysis, comparing the big vendors of Diameter Signalling is available here.

Access Network Signalling Storm:

My thinking is that the Core Network Signalling problem will become an issue some years down the road whereas the Access Network Signalling problem will be seen sooner rather than later. In fact for 3G/HSPA the problem is becoming more visible as the market has matured and more and more users are moving towards using smartphones, Since LTE rollouts are in its infancy (in most markets) the problem is still some way away.

One of the reasons for Signalling storm is the incorrect APN name. I reported earlier about Telefonica's approach to solve this problem by using 'Parking APN', see here.

Also embedded below are couple of presentations from the Signalling Focus day that talk about the problem from Access Network point of view

Other Interesting Reading Material

Finally there is an excellent whitepaper from Heavy Reading titled "The Evolution of the Signalling Challenge in 3G & 4G networks", available here to download.

Another excellent article summarising the problem is from Huawei magazine available here.

Monday, 16 January 2012


Interesting report to remind the differences between HSPA and LTE available here.

Monday, 21 November 2011

HSDPA multiflow data transmission

From RP-111375:

HSPA based mobile internet offerings are becoming very popular and data usage is increasing rapidly. As a result, HSPA has begun to be deployed on more than one transmit antenna and/or on more than one carrier. As an example, the single cell downlink MIMO (MIMO-Physical layer) feature was introduced in Release 7. This feature allowed a NodeB to transmit two transport blocks to a single UE from the same cell on a pair of transmit antennas thus improving data rates at high geometries and providing a beamforming advantage to the UE in low geometry conditions. Subsequently, in Release-8 and Release-9, the dual cell HSDPA (DC-HSDPA) and dual band DC-HSDPA features were introduced. Both these features allow the NodeB to serve one or more users by simultaneous operation of HSDPA on two different carrier frequencies in two geographically overlapping cells, thus improving the user experience across the entire cell coverage area.

When a UE falls into the softer or soft handover coverage region of two cells on the same carrier frequency, the link from the serving HS-DSCH cell is capacity or coverage limited and the non-serving cell in its active set has available resources, it would be beneficial to schedule packets to this UE also from the non-serving cell and thereby improve this particular user’s experience.

One family of such schemes parses the incoming data for the user into multiple (restricted to two cells in the study) data streams or flows, each of which is transmitted from a different cell [8] Concurrent transmission of data from the two cells may either be permitted or the UE may be restricted to receiving data from only one cell during a given TTI. The former type of scheme is designated an aggregation scheme while the latter is termed a switching scheme. The aggregation scheme can be seen as subsuming the switching scheme at the network when scheduling to the user is restricted to the cell with better channel quality.

Figure 14 illustrates the basic multi-flow concept with both cells operating on the same carrier frequency F1.

3GPP studied different multipoint transmission options for HSDPA and documented the findings and performance gains in TR25.872 providing feasibility and performance justification for the specification work.

For more details also see:
See also old blog post on Multipoint HSDPA/HSPA here.

Wednesday, 14 September 2011

Inter-technology Carrier Aggregation

Another one from the 4G Americas whitepaper of Mobile Broadband explosion:

Carrier aggregation will play an important role in providing operators maximum flexibility for using all of their available spectrum. By combining spectrum blocks, LTE-Advanced will be able to deliver much higher throughputs than otherwise possible. Asymmetric aggregation (i.e., different amounts of spectrum used on the downlink versus the uplink) provides further flexibility and addresses the fact that currently there is greater demand on downlink traffic than uplink traffic. Specific types of aggregation include:

  • Intra-band on adjacent channels.
  • Intra-band on non-adjacent channels.
  • Inter-band (e.g., 700 MHz, 1.9 GHz).
  • Inter-technology (e.g., LTE on one channel, HSPA+ on another). This is currently a study item for Release 11. While theoretically promising, a considerable number of technical issues will have to be addressed.

Friday, 2 September 2011

Multipoint HSDPA / HSPA

The following is from 3GPP TR 25.872 - Technical Specification Group Radio Access Network; HSDPA Multipoint Transmission:

HSPA based mobile internet offerings are becoming very popular and data usage is increasing rapidly. Consequently, HSPA has begun to be deployed on more than one transmit antenna or more than one carrier. As an example, the single cell downlink MIMO (MIMO-Physical layer) feature was introduced in Release 7. This feature allowed a NodeB to transmit two transport blocks to a single UE from the same cell on a pair of transmit antennas thus improving data rates at high geometries and providing a beamforming advantage to the UE in low geometry conditions. Subsequently, in Release-8 and Release-9, the dual cell HSDPA (DC-HSDPA) and dual band DC-HSDPA features were introduced. Both these features allow the NodeB to serve one or more users by simultaneous operation of HSDPA on two different carrier frequencies in two geographically overlapping cells, thus improving the user experience across the entire cell coverage area. In Release 10 these concepts were extended so that simultaneous transmissions to a single UE could occur from four cells (4C-HSDPA).

When a UE falls into the softer or soft handover coverage region of two cells on the same carrier frequency, it would be beneficial for the non-serving cell to be able to schedule packets to this UE and thereby improving this particular user’s experience, especially when the non-serving cell is partially loaded. MultiPoint HSDPA allows two cells to transmit packets to the same UE, providing improved user experience and system load balancing. MultiPoint HSDPA can operate on one or two frequencies.

Click to enlarge

There is also an interesting Qualcomm Whitepaper on related topic that is available to view and download here. The following is from that whitepaper:

The simplest form of Multipoint HSPA, Single Frequency Dual Cell HSPA (SFDC-HSPA), can be seen as an extension to the existing DC-HSPA feature. While DC-HSPA allows scheduling of two independent transport blocks to the mobile device (UE) from one sector on two frequency carriers, SFDC-HSPA allows scheduling of two independent transport blocks to the UE from two different sectors on the same carrier. In other words, it allows for a primary and a secondary serving cell to simultaneously send different data to the UE. Therefore, the major difference between SFDC-HSPA and DC-HSPA operation is that the secondary transport block is scheduled to the UE from a different sector on the same frequency as the primary transport block. The UE also needs to have receive diversity (type 3i) to suppress interference from the other cell as it will receive data on the same frequecny from multiple serving cells.Figure 1 llustrates the high-level concept of SFDC-HSPA.

In the case where the two sectors involved in Multipoint HSPA transmission belong to the same NodeB (Intra-NodeB mode), as illustrated in Figure 2, there is only one transmission queue maintained at the NodeB and the RNC. The queue management and RLC layer operation is essentially the same as for DC-HSPA.

In the case where the two sectors belong to different NodeBs (Inter-NodeB mode), as illustrated in Figure 2, there is a separate transmission queue at each NodeB. RLC layer enhancements are needed at the RNC along with enhanced flow control on the Iub interface between RNC and NodeB in order to support Multipoint HSPA operation across NodeBs. These enhancements are discussed in more detail in Section 4. In both modes, combined feedback information (CQI and HARQ-ACK/ NAK) needs to be sent on the uplink for both data streams received from the serving cells. On the uplink, the UE sends CQIs seen on all sectors using the legacy channel structure, with timing aligned to the primary serving cell.

When two carriers are available in the network, there is an additional degree of freedom in the frequency domain. Dual Frequency Dual Cell HSPA (DFDC-HSPA) allows exploiting both frequency and spatial domains by scheduling two independent transport blocks to the UE from two different sectors on two different frequency carriers. For a DC-HSPA capable UE, this is equivalent to having independent serving cells on the two frequency carriers. In Figure 3, UE1 is in DC-HSPA mode, whereas UE2 is in DFDC-HSPA mode.

Dual Frequency Four-Cell HSPA (DF4C-HSPA) can be seen as a natural extension of DFDC-HSPA, suitable for networks with UEs having four receiver chains. DF4C-HSPA allows use of the four receiver chains by scheduling four independent transport blocks to the UE from two different sectors on two different frequency carriers. DF4C-HSPA is illustrated in Figure 4.

Like SFDC-HSPA; DFDC-HSPA and DF4C-HSPA can also be intra-NodeB or inter-NodeB, resulting in an impact on transmission queue management, Iub flow control and the RLC layer.

Advantages of Multipoint transmission:
* Cell Edge Performance Improvement
* Load balancing across sectors and frequency carriers
* Leveraging RRU and distributed NodeB technology

Multipoint HSPA improves the performance of cell edge users and helps balance the load disparity across neighboring cells. It leverages advanced receiver technology already available in mobile devices compatible with Release 8 and beyond to achieve this. The system impact of Multipoint HSPA on the network side is primarily limited to software upgrades affecting the upper layers (RLC and RRC).

Sunday, 19 December 2010

Multicarrier and multiband HSPA aggregation

From NSN Whitepaper on HSPA Evolution:

HSPA Release 10 with 4-carrier HSDPA provides a peak downlink data rate of 168 Mbps using 2x2 MIMO (Multiple Input Multiple Output) over the 20 MHz bandwidth. This matches the LTE Release 8 data rates obtained using comparable antenna and bandwidth configurations. A natural next step for the HSPA Release 10 downlink is to further extend the supportable bandwidths to 40 MHz with 8-carrier HSDPA, doubling the Release 10 peak rate to 336 Mbps.

8-carrier HSDPA coupled with 4x4 MIMO doubles the peak rate again to reach 672 Mbps, see Figure 1. The evolution of HSPA beyond Release 10 will push the peak data rates to rival those provided by LTE Advanced.

In addition to increased peak rates, the aggregation of a larger number of carriers improves spectrum utilization and system capacity owing to inherent load balancing between carriers. Additional capacity gains from trunking and frequency domain scheduling will also be seen.

Typical spectrum allocations do not provide 40 MHz of contiguous spectrum. To overcome spectrum fragmentation, HSDPA carrier aggregation allows carriers from more than one frequency band to be combined. 3GPP Release 9 already makes it possible to achieve 10 MHz allocation by combining two 5 MHz carriers from different frequency bands, such as one carrier on 2100 MHz and another on 900 MHz.

The 4-carrier HSDPA of Release 10 extends this further, allowing the aggregation of up to four carriers from two separate frequency bands. Long Term HSPA Evolution allows eight carriers. Typical cases of HSDPA multiband aggregation are shown in Figure 2.

Wednesday, 20 October 2010

Fast Dormancy in Release-8

Nokia Siemens Networks has collaborated with Qualcomm to carry out the industry’s first successful interoperability test of the new 3GPP standardized Release 8 Fast Dormancy feature. Unlike proprietary approaches to fast dormancy, the new standard allows operators to take full advantage of smart network features such as Cell_PCH without worrying that individual handset settings will ignore network controls.

The test was conducted at Nokia Siemens Networks’ Smart Lab in Dallas using Nokia Siemens Networks’ Flexi Multiradio Base Station and Radio Network Controller and Qualcomm’s QSC7230TM smartphone optimized chipset. The test showed how smartphones can act dynamically, exploiting Cell_PCH on Nokia Siemens Networks’ smart networks or adjusting to Fast Dormancy on other vendors’ traditional networks.

In fact the operators have been getting upset quite for some time because of smartphone hacks that save the UE battery life but cause network signalling congestion. See here.

To explain the problem, lets look at the actual signalling that occurs when the UE is not transmitting anything. Most probably it gets put into CELL_PCH or URA_PCH state. Then when keep alive messages need to be sent then the state is transitioned to CELL_FACH and once done its sent back to CELL_PCH. Now the transitioning back from CELL_FACH (or CELL_DCH) to CELL_PCH can take quite some time, depending on the operator parameters and this wastes the UE battery life.

To get round this problem, the UE manufacturers put a hack in the phone and what they do is that if there no data to transmit for a small amount of time, the UE sends RRC Signalling Connection Release Indication (SCRI) message. This message is supposed to be used in case when something is gone wrong in the UE and the UE wants the network to tear the connection down by sending RRC Connection Release message. Anyway, the network is forced to Release the connection.

If there is another requirement to send another keep alive message (they are needed for lots of apps like Skype, IM's, etc.) the RRC connection would have to be established all over again and this can cause lots of unnecessary signalling for the network causing congestion at peak times.

To speed up the transitioning to CELL_PCH state in Release-8 when the UE sends SCRI message, its supposed to include the cause value as "UE Requested PS Data session end". Once the network receives this cause it should immediately move the UE to CELL_PCH state.

This is a win win situation for both the network and the UE vendors as long as a lot of UE's implement this. The good thing is that even a pre-Rel8 UE can implement this and if the network supports this feature it would work.

GSMA has created a best practices document for this feature which is embedded below.

Further Reading:

Thursday, 30 September 2010

RF Pattern Matching adopted in 3GPP Release-10

RF Pattern Matching is now a recognized unique location method in standards that provides carriers and OEMs with the ability to offer high accuracy location-based services that traditionally haven’t been available with low-accuracy Cell-ID based technologies. RF Pattern Matching will be incorporated into Release 10 of the 3G UMTS specifications, expected to become final in late 2010 or early 2011. This will also set the stage for opportunities to incorporate RF Pattern Matching into LTE and other future air interfaces.

“The decision to incorporate RF Pattern Matching into the 3G UMTS specifications is needed for all service providers wanting to provide the highest-SLA option for LBS as it gives them more credible options for public safety and commercial applications,” said Manlio Allegra, president and chief executive officer at Polaris Wireless. “This level of LBS accuracy will create an improved user experience for wireless customers, which ultimately generates additional revenue streams for carriers and other enterprises offering LBS applications.”

Polaris WLS™ is a patent-protected implementation of RF Pattern Matching, which provides the best network-based location performance in urban and indoor settings and is a perfect complement to A-GPS, enabling a best-in-class hybrid solution. Polaris’ WLS™ works without the RF Pattern Matching definition in standards, but standardization through 3GPP allows for future performance enhancements and provides flexibility for the solution and carrier implementations. Polaris’s current WLS products will continue to operate within existing standards.

By being included in the 3G UMTS standard, Polaris’ location technology has received further validation as one of the most accurate in the world. Polaris will now be considered a preferred provider to Tier 1 carriers and infrastructure vendors who want to add a high accuracy location solution to their technology mix that meets the new 3GPP standard.

The FCC is currently considering new E911 Phase II regulations that would improve indoor location capabilities for first responders. Using RF Pattern Matching, Polaris’ WLS™ software solution enables carriers and OEMs to be prepared to meet these new FCC requirements with little or no investment in new infrastructure or hardware.

RF Pattern Matching Discussion document presented in 3GPP is embedded below:

Tuesday, 28 September 2010

SIMFi = SIM with WiFi

Since the beginning of this year, Sagem Orga and Telefonica have been working on next generation SIM card called SIMFi.

With SIMFi, you can convert a phone into a WiFi hotspot. The phone would use HSPA/LTE for data connectivity and at the same time it would broadcast WiFi signals for any equipment to connect to these signals and browse the web. Power consumption information have not been mentioned which I am sure would be a problem for the phone.

SIMFi Removes the need for additional accessories to facilitate transmission services (e.g. MiFi, USB modem, PCMCIA…) and can make connectivity a lot simpler, straigtforward and cheaper.

SIMFi specifications
  • SIM card compatible with the latest telecom specifications.
  • SIM card: ISO 2FF plug-in
  • The mobile phone does not need any special features.
  • Modem WiFi integrated in the SIM card, works with 802.11b.
  • The modem is guided by the SIM card's tools.
  • Energy-saving features (works with 2G and 3G).
  • The aerial is adaptable, allowing short- and long-range operations (from 2 cm to 30 m) managed by the SIM card's tools.

Tuesday, 14 September 2010

Femtocell Interference Management in real life

Couple of years back we blogged about the Femtocell Inteference in Macro network. Since then things have moved on a long way. There are commercial rollouts happening with Vodafone leading the way. Yesterday, I was reading Prof. Simon Saunders article on Femtocell and the following struck me.

A major technical challenge that femtocell designers initially faced was the need to manage potential interference. It takes up to two years to install conventional base stations, during which time radio engineers meticulously plan a station’s position and radio characteristics to avoid interference. However, such an approach is not viable in the case of femtocells, deployed potentially in their millions at random. Automating a process conducted by radio engineers was no mean feat and simply would not have been possible a few years ago.

Fortunately, the fact that the walls of buildings keep 3G signals out and keep the femtocell’s signals in provides strong inherent interference mitigation for indoor femtocells. Extensive studies have shown that proper implementation of a few key techniques to reduce interference can take advantage of this attenuation in an intelligent manner. Such techniques include frequent monitoring of the cell’s surrounding radio environment combined with adaptive power control. Indoor users gain faster data rates, as do outdoor users who now operate on less congested cells, while it costs less for operators to deliver higher overall network capacity. Large-scale, real-world deployments are demonstrating that these techniques work in practice and even allow new approaches, such as operating 3G networks in the same spectrum as 2G networks.

AT&T has deployed femtocells on the same frequencies as both the hopping channels for GSM macrocells and with UMTS macrocells. They have tested thousands of femtocells, and found that the mitigation techniques implemented successfully minimise and avoid interference. The more femtocells are deployed, the more uplink interference is reduced.

It is very interesting to see that the interference is not causing any problems in real life.

Back in Feb, Femto Forum released a new report on "Interference Management in UMTS Femtocells". A similar report was released in Dec. 08. Then in March they released a similar report for OFDMA (covering both LTE and WiMAX) femtocells. They are interesting reading for those who are interested in this area.

European Union is having a similar program called FREEDOM (Femtocell-based network enhancement by interference management and coordination of information for seamless connectivity ). FREEDOM focuses on:
  • Advanced interference-aware cooperative PHY techniques,
  • Improvement of the control plane procedures for seamless connectivity, and
  • System-level evaluation and hardware demonstrator of the proposed femto-based network architecture.

More info on their website ( You can see their scenario document that shows different interference scenarios and also compares different approaches including those of Femto Forum, 3GPP and WiMAX.

Thursday, 12 August 2010

Whitepaper: Traffic Management Techniques for Mobile Broadband Networks

The report, Traffic Management Techniques for Mobile Broadband Networks: Living in an Orthogonal World,focuses on 3GPP networks and concerns itself specifically with traffic management, including the handling of traffic flows on 3GPP networks in contrast with other network management techniques that operators may deploy (such as offloading, compression, network optimization and other important mechanisms).

Mobile broadband networks are confronted by a number of challenges. In particular, the physical layer in mobile networks is subject to a unique confluence of unpredictable and unrelated, or “orthogonal,” influences. Moreover, mobile broadband networks have some important differences from their fixed brothers and sisters, which lead to different traffic management requirements. Among the most significant differences for purposes of traffic management is the need for more granular visibility to circumstances on the ground. Optimally, traffic management for mobile broadband networks requires visibility to what is occurring (by device or application) at the cell site level and in a timeframe that enables as far as feasible near-time reactions to resolve issues.

With the consumer in mind, an End-to-End (E2E) view of mobile service is critical for traffic management. For example, a consumer using a mobile phone to look up movie listings and purchase tickets considers the E2E service as the ability to see what movie is playing and execute a transaction to purchase tickets. 3GPP has endeavored to standardize increasingly more robust traffic management (Quality of Service, or QoS) techniques for mobile broadband networks with a consumer’s E2E view of QoS. It must be considered, however, that mobile operators typically do not have full control over E2E provisioning of services that depend on mobile broadband Internet access.

Global standards organizations like 3GPP play an important role in the development of traffic management through provisions for addressing QoS, particularly regarding interworking with non-3GPP access mechanisms. These are important new innovations, and the 3G Americas white paper notes that the efforts of standards development organizations should be intensified.

In addition, the configuration of end-user devices and content and applications not provisioned by the network operator not only impacts the experience of the particular user, but potentially other users in a particular cell as well. Efforts to drive further QoS innovations should be mindful of potentially adverse impacts from these sources and support and foster interoperability of third party applications with existing network platforms.

More innovations are needed throughout the mobile broadband ecosystem, in particular by application developers, in order to realize E2E quality of service. Furthermore, transparency in network management practices is important in fostering innovation, but requires a careful balancing to ensure consumer comprehension while safeguarding network reliability. Organizations with technical expertise such as 3G Americas are prepared to help to illuminate and progress the development of these new technologies.

“3G Americas stands ready to assist interested parties in the ongoing development and understanding of traffic management techniques,” said Chris Pearson, President of 3G Americas. “We are mindful that in this hemisphere and elsewhere, the industry has accepted an increasingly active role in addressing questions about service levels and innovation on mobile broadband networks.”

The white paper, Traffic Management Techniques for Mobile Broadband Networks: Living in an Orthogonal World, was written collaboratively by members of 3G Americas and is available for free download on the 3G Americas website at

Friday, 28 May 2010

UMTS/HSPA State Transition Problems to be solved with LTE

The way UMTS/HSPA is designed is that the Mobile (UE) is always in IDLE state. If there is some data that needs to be transferred then the UE moves to CELL_DCH. If the amount of data is very less then the UE could move to CELL_FACH state. The UE can also move to CELL_PCH and URA PCH if required but may not necessarily do so if the operator has not configured those states.

The problem in UMTS/HSPA is that these state transitions take quite some time (in mobile terms) and can slow down the browsing experience. Martin has blogged about the state transition problems because of the keep alive messages used by the Apps. These small data transfers dont let the UE go in the IDLE state. If they do then whole raft of signalling has to occur again for the UE to go to CELL_FACH or CELL_DCH. In another post Martin also pointed out the sluggishness caused by the UE in CELL_FACH state.

Mike Thelander of the Signals Research Group presented similar story in the recently concluded LTE World Summit. It can be seen from the figure above that moving from IDLE to CELL_DCH is 1-3secs whereas FACH to DCH is 500ms.

In case if some Apps are running in the background, they can be using these keep alive messages or background messages which may be very useful on the PC but for the Mobiles, these could cause unnecessary state transitions which means lots of signalling overhead.

The Apps creators have realised this problem and are working with the Phone manufacturers to optimise their messaging. For example in case of some Apps on mobiles the keep alive message has been changed from 20 seconds to 5 mins.

3GPP also realised this problem quite a while back and for this reason in Release-7 two new features were added in HSPA+. One was Continuous Packet Connectivity (CPC) and the other was Enhanced CELL_FACH. In Release-8 for HSPA+, these features were added in UL direction as well. The sole aim of these features were to reduce the time it would take to transit to CELL_DCH. Since CPC increases the cell capacity as well, more users can now be put in CELL_FACH instead of being sent to IDLE.

An interesting thing in case of LTE is that the RRC states have been simplified to just two states as shown here. The states are IDLE and CONNECTED. The intention for LTE is that all the users can be left in the CONNECTED state and so unnecessary signalling and time spent on transitioning can be reduced.

The preliminary results from the trials (as can also be seen from here) that were discussed in the LTE World Summit clearly show that LTE leads to a capacity increase by 4 times (in the same BW) and also allow very low latency. I am sure that enough tests with real life applications like Skype, Fring and Yahoo IM have not been done but I am hopeful of the positive outcome.

Tuesday, 13 April 2010

HSPA finds success with Mobile Broadband Growth

Another GSA report titled "Mobile Broadband Growth - Reports from HSPA Operators Worldwide". As the name suggests, this contains report from different operators on their Mobile Broadband revenues growth.

Some interesting bits from the report:
  • According to a report from AdMob, smartphonedata traffic grew 193% year-over-year in the month of February 2010. Smartphonesaccounted for 48% of its traffic in February 2010, up from 35% the year before. AdMobattributed this primarily to iPhoneand Android traffic.
  • Deutsche Telekom CEO René Obermann is expected to double revenues by 2015 with €10 billion coming from mobile data traffic. Obermann said it would double the number of 3G smartphonesin the network to around 8 million by the end of 2010
  • A recent report by In-Stat, stated that mobile broadband is now the second-largest access technology behind DSL, making up 18% subscribers
  • Telia Sonera reported that the strong demand for mobile devices, including mobile broadband and Apple iPhone™, continued. Mobile data traffic in Nordic and Baltic operations increased close to 200% while the number of mobile broadband subscriptions rose by more than 60% during 2009.
  • AT&T reported that Text messaging grew 50% YoY and picture messaging grew 130%
  • According to IDC's Worldwide Quarterly Mobile Phone Tracker, vendors shipped a total of 54.5 million units Q4 09, up 39.0% from Q4 08. Vendors shipped a total of 174.2m units in 2009, up 15.1% from the 151.4m units in 2008. Converged mobile devices accounted for 15.4% of all mobile phones shipped in 2009, up slightly from 12.7% in 2008
  • The number of people subscribing to broadband internet services in Australia grew rapidly with wireless broadband and 3G mobile services continuing strong growth in 2009, according to a new report by ACMA (Australian Communications and Media Authority). 3G now accounts for more than 50% of all mobile subscriptions, an annual increase of 44%. Internet subscriptions reached 8.4 million in June 2009, compared to 7.2 million in June 2008. Broadband subscriptions increased from 5.66 million to 6.72 million in the same period, with wireless subscribers gaining 162% to 2.1 million
  • Vodafone's Data traffic has risen 300% in the past two years. Data now represents 11% of all European service revenues. Smartphones represent 20% of handsets sales. Around 40% of the company's European 3G/HSPA networks now support 7.2 Mbps. In the coming 6 months, Vodafone plans to upgrade 20-25,000 sites across Europe to HSPA+
  • UK consultancy firm, Coda Research Consultancy, has predicted that mobile data consumption in the US is set to reach 327,000 terabytes a month by 2015, indicating a 40-fold rise in mobile data consumption over 5 years
  • Mobile data traffic from PC modems and routers is forecast to increase 4-fold between 2010 and 2014, according to a report by ABI Research. 2,000 petabytes of data will be sent and received in 2010, a figure that will rise to about 8,000 petabytesin 2014
  • Semiannual US wireless industry survey was released at CTIA in March 2010 revealing that wireless service revenues totaled $77 billion for the last half of the year. The real growth is coming from wireless data services -mobile Web, text messages, and other non-voice services. In the latter half of last year, revenue for wireless data service totaled > $22 billion, nearly a third of overall wireless services revenue and up 26% YoY. Steve Largent, President and CEO of CTIA, said in a statement. "Mobile broadband will increasingly play a vital role in people’s lives."
  • A new study by Juniper Research has forecast that more than 1 in 10 mobile subs will either have a ticket delivered to their mobile phone or buy a ticket with their phone by 2014, representing a five-fold growth over the next five years.
  • Strategy Analytics recently forecast that the number of active mobile broadband subscriptions worldwide is expected to rise to around 1.3 billion by 2014
  • ABI Research announced that shipments of mobile broadband-enabled consumer products, which includes e-book readers, mobile digital cameras, camcorders, personal media players, personal navigation devices and mobile gaming devices will increase 55-fold between 2008 and 2014 with total shipments reaching 58 million units per year in 2014