Showing posts with label Carrier Aggregation. Show all posts
Showing posts with label Carrier Aggregation. Show all posts

Tuesday, 11 September 2012

New Carrier-Aggregation Proposed Bands

Carrier Aggregation (CA) the promised feature of LTE-A that will make it compatible to IMT-A is not fully exploited in Rel-10. There are only 2 bands supported for CA in Rel-10 and the same for Rel-11. The following are the bands for Rel-10

And the following for Rel-11

Unfortunately these are not enough for all the operators launching LTE/LTE-A. As a result there is currently a study on lots of other bands ongoing within 3GPP. Here is my understanding of the bands that would be needed and the region where they would be needed. Interested in knowing if there are other operators/regions where other bands need to be included.
 

Monday, 18 June 2012

3GPP Release-12 and beyond


3GPP Recently held a workshop on "Release 12 and Onward" to identify common requirements for future 3GPP radio access technologies. The goal of the workshop is to investigate what are the main changes that could be brought forward to evolve RAN toward Release 12 and onward. It is recommended that presentations in the workshop include views on:
- Requirements
- Potential technologies
- Technology roadmap for Releases 12, 13 and after

The discussions from the workshop should be used to define the work plan for Release 12 and onward in TSG-RAN.

The list of presentations and links, etc. are below and I have also embedded the Summary and Draft report, both of which can be downloaded from 3GPP website or slideshare. Here is a list of different topics and the presentations that covered them:


AdHoc Networks
AdHoc Networks - RWS-120035


Antennas, Beamforming, Transmitters, Receivers
3D-beamforming - RWS-120002
Vertical sectorization/3D beamforming via AAS - RWS-120005
Advanced receivers and joint Tx/Rx optimisation - RWS-120005
Network assistance for IC receivers - RWS-120005
Support of Active Antenna Systems - RWS-120006
Advanced transmitter beamforming - RWS-120010
Advanced receiver cancellation - RWS-120010
Vertical and 3D beamforming - RWS-120011
MIMO Enhancements - RWS-120014
New antenna configurations and 3D MIMO - RWS-120014
UE AAS (Active Antenna System) [Detailed] - RWS-120015 / RWS-120049
Cloud of Antennas (CoA) Concept - RWS-120016
Support of Massive MIMO Technology - RWS-120016
Full Dimension MIMO (FD-MIMO) System [Detailed] - RWS-120021 / RWS-120046
Cloud-RAN: Benefits and Drawbacks - RWS-120021 / RWS-120046
Further Enhanced Receivers - RWS-120022
Multiple antenna evolution - RWS-120025
3D beamforming - RWS-120026
Vision of 3D MIMO - RWS-120029
Massive MIMO & 3D MIMO - RWS-120034
Potential MIMO Enhancements - RWS-120035
Advanced Antenna Technology - RWS-120035
DL MIMO Enhancement - RWS-120037
Performance Requirement for 8Rx at eNB - RWS-120037
UE Receiver Enhancements - RWS-120039
DL MU-MIMO Enhancement - RWS-120039
Enhancement of MIMO, CoMP - RWS-120040
Advanced MIMO - RWS-120040
MIMO and COMP - RWS-120041
Role of Advanced Receivers - RWS-120041
Advanced Interference Handling - RWS-120041
Interference Suppression Subframes (ISS) and IRC Receiver [Detailed] - RWS-120051


Applications (Apps)
Efficiency for diverse small data applications - RWS-120011
Device Service/Application Awareness - RWS-120018
I-Net:”I”-centric mobile network design philosophy - RWS-120024
Application Aware Comm - RWS-120036 / RWS-120050


Backhaul and Relay
Relay backhaul enhancement - RWS-120011
LTE Backhaul - RWS-120013
Relay - RWS-120025
CoMP, backhaul and X2 interface - RWS-120027 / RWS-120048
Mobile Relay And Relay Backhaul Enhancement - RWS-120029


Baseband
Baseband resource pooling and virtualization - RWS-120011


Capacity and Coverage
Higher system capacity - RWS-120010
Capacity for Mobile Broadband: Requirements and Candidate technologies - RWS-120012
Increase N/W capacity by 1000 times - RWS-120020
Coverage Enhancement - RWS-120037
Capacity Enhancement - RWS-120038 / RWS-120047
Cell-edge Throughput Improvement - RWS-120038 / RWS-120047


Carrier Aggregation, Flexible Bandwidths and Multiflow
LTE multiflow / Inter-site CA - RWS-120002
LTE/HSDPA Carrier Aggregation - RWS-120002
Multiflow Enhancements - RWS-120002
Multi-Stream Aggregation - RWS-120006
Provide mechanisms for Flexible Bandwidth Exploitation - RWS-120008
Carrier aggregation enhancement - RWS-120019
Inter-eNB Carrier Aggregation - RWS-120021 / RWS-120046
Evolution of Carrier Aggregation - RWS-120036 / RWS-120050
CA of Alternative Spectra - RWS-120042


Cells, Carriers, C/U Planes
C/U plane split & Phantom cell - RWS-120010
Phantom cell by single/separate nodes - RWS-120010
Phantom cell: Other topics - RWS-120010
New Carrier Type for Primary Component Carrier - RWS-120011
Flexible/Reconfigurable Cells - RWS-120023
New carrier-type (NCT) enhancements - RWS-120026
Amorphous cells - RWS-120034
New Carrier Types - RWS-120035
Non-Orthogonal Access - RWS-120039
Dynamic Area Construction for UE - RWS-120040


Cognitive Radio
Cognitive radio - RWS-120034
Cognitive Networking - RWS-120036 / RWS-120050


Coordinated MultiPoint (CoMP)
CoMP Enhancements - RWS-120014
CoMP/ICIC enhancement - RWS-120019
CoMP Enhancements - RWS-120023
CoMP enhancements - RWS-120026
CoMP Technologies - RWS-120027 / RWS-120048
Enhanced CoMP - RWS-120029
Potential CoMP Enhancements - RWS-120035
CoMP - RWS-120037
CoMP Enhancement for Indoor Environment - RWS-120040
Overhauling DL CoMP - RWS-120042


Device, Handsets, UE's
Additional UE Enhancements - RWS-120018
Coordination : Multi-mode UE - RWS-120024


D2D / Device-to-Device
Device-to-Device - RWS-120003
LTE Device to Device - Proximity Based Services - RWS-120004
LTE device to device - RWS-120007
LTE direct communication - RWS-120007
Device-to-Device Communications - RWS-120014
D2D Discovery/Communication - RWS-120016
3GPP Proximity Services (ProSe) / D2D - RWS-120022
Device-to-Device communications - RWS-120026
Device-to-Device communication - RWS-120036 / RWS-120050


Data Rates and Throughputs
Higher data rate and user-experienced throughput - RWS-120010
Fairness of user throughput - RWS-120010


Deployments
LTE in Local Area Deployments & Enhancements - RWS-120004
Energy Efficient Local Area Deployments - RWS-120004
Scaling for Mass Deployment - RWS-120008
Flexible and cost-efficient NW deployments - RWS-120010
Considerations on dense NW deployment - RWS-120019


Energy Consumption, Efficiency and Savings
Energy efficiency - RWS-120005
Reduce energy consumption - RWS-120008
Energy Saving - RWS-120014
UE Power Saving - RWS-120036 / RWS-120050
NB Power Saving - RWS-120036 / RWS-120050
Energy Saving Enhancements with CoMP - RWS-120040
Energy Saving with Centralized eNB - RWS-120040


Herogeneous Networks (HetNets)
Optimisation of Het Nets performance - RWS-120005
Improved Support for Heterogeneous Networks - RWS-120006
Network hyper-densification: LTE HetNet2.0 - RWS-120007
Multi-layer HetNet Deployments - RWS-120016
HetNet for HSPA - RWS-120017
HetNet Enhancements - RWS-120023
HetNet Mobility - RWS-120029
Small cells & HetNet - RWS-120031
HetNet - RWS-120037
HetNet Enhancements for HeNB - RWS-120040


HSDPA / HSUPA / HSPA+ Enhancements
HSPA UL Enhancements - RWS-120003
Uplink Enhancements - RWS-120006
UMTS evolution: enhancing CS voice on DCH - RWS-120007
High Speed Packet Access - RWS-120012
HSPA RRM enhancement - RWS-120024
HSPA+ further evolution - RWS-120034


Interworking (HSPA, LTE)
Coordination : HSPA/LTE e-interworking - RWS-120024
Inter-RAT Coordination/CA - RWS-120037


Local-Area Access (Small Cells)
Local-Area Access - RWS-120003
LTE in Local Area Deployments & Enhancements - RWS-120004
LTE Local Area Enhancements - RWS-120004
LTE Local Area Enhancement Areas - RWS-120004
enhanced Local Area (eLA) - RWS-120010
Local Area Enhancements - RWS-120022
Improved Local Area Mobility - RWS-120022


LTE
LTE for Nomadic and Fixed Use - RWS-120018
E-PDCCH enhancement - RWS-120019
Efficiency : Paging Optimization - RWS-120024


LTE Hotspot and Indoor Enhancements (LTE-Hi)
Hotspot and Indoor Enhancements (LTE-Hi) - RWS-120006
Hotspot/indoor Scenario (LTE-Hi) - RWS-120025
Indoor & Hotspot Enhancements (LTE-Hi) [Detailed] - RWS-120029
Possible Study Items for Indoor Environment - RWS-120040


M2M / Machine Type Communications (MTC)
Machine Type Communications - RWS-120003
Improved Support for MTC - RWS-120006
Machine-to-Machine: The Internet of Things - RWS-120014
Machine Type Communications: a new ecosystem - RWS-120014
Wireless MTC and RAN optimizations for MTC - RWS-120016
Low-Cost MTC UE - RWS-120017
MTC + eDDA (enhanced Diverse data application) - RWS-120019
Further Enhancements to Support MTC - RWS-120023
MTC - RWS-120025
MTC enhancements - RWS-120026
M2M - RWS-120029
MTC and migration of traffic from 2G - RWS-120031
Machine Type Communications enhancements - RWS-120034
Machine Type Communications - RWS-120035
Extension triggered by growing M2M traffic - RWS-120038 / RWS-120047
LTE-based M2M - RWS-120041


MBMS / eMBMS
eMBMS Enhancements - RWS-120007
eMBMS - RWS-120013
UHD Multimedia Broadcast/Multicast Service - RWS-120036 / RWS-120050


Mesh Networks
Mesh Networks - RWS-120018


Network Density
Network density: Scenarios - RWS-120010


Network Architecture and Operation
Easier network operation, tolerance to failure - RWS-120005
System Architecture - RWS-120032
Evolution of LTE Networks - RWS-120034


Positioning
Positioning Enhancements - RWS-120006


Public Safety
Public Safety - RWS-120030
Operation of Public Safety System via LTE - RWS-120031
Public safety’s future in LTE [Detailed] - RWS-120033


Self Organising Networks (SON) and Minimisation of Drive Testing (MDT)
SON Evolution - RWS-120002
Enhanced MDT - RWS-120011
Network Self-Optimisation - RWS-120014
SON and MDT - RWS-120017
HetNet SON - RWS-120029
MDT & Energy Saving - RWS-120029
Autonomous Interference Coordination - RWS-120029
Large scale multi-layer centralized cooperative radio - RWS-120034
MDT Enhancement - RWS-120036 / RWS-120050
SON Enhancements - RWS-120036 / RWS-120050
MDT and eDDA - RWS-120041


Small Cells (HNB/HeNB)
UMTS evolution: small cells - RWS-120007
Wide & Local area enhancements - RWS-120010
Small Cells - RWS-120014
Small Cell Enhancement in Rel-12 - RWS-120021 / RWS-120046
HeNB Enhancement - RWS-120036 / RWS-120050
Efficient Usage of Macro and Small Cells - RWS-120038 / RWS-120047
Low-cost Low Power Nodes (LC-LPN) - RWS-120038 / RWS-120047
Small-Cell Improvements: System Aspects - RWS-120041


Spectrum
Enhanced spectrum efficiency - RWS-120005
Spectrum efficiency: eLA topics - RWS-120010
Scenarios for spectrum extension - RWS-120010
Spectrum and spectrum usage - RWS-120012
Wider Spectrum Utilization - RWS-120016
Spectral efficiency for LTE - RWS-120017
New Spectrum for Mobile Broadband Access - RWS-120021 / RWS-120046
Enabling Technologies for New Spectrum - RWS-120021 / RWS-120046
Radio Propagation - RWS-120021 / RWS-120046
Opportunistic Use of Unlicensed Spectrum for D2D Local Traffic - RWS-120023
Flexible Spectrum Utilization - RWS-120024
Spectrum Related: New Bands And CA Band Combinations - RWS-120029
Spectrum - RWS-120032
Hybrid access scheme - RWS-120034
Spectrum - RWS-120035
Spectrum and Transmission Efficiency - RWS-120039
Spectrum-Agile LTE - RWS-120041


TDD / TD-LTE
TD-LTE - RWS-120014
TDD-specific aspects - RWS-120014
TDD adaptive reconfiguration - RWS-120034
Efficient Usage of Dual Duplex Modes - RWS-120038 / RWS-120047
LTE TDD Small-Cell versus WiFi - RWS-120041


Testing
Testing and Certification - RWS-120022


Traffic and Signalling Overhead
Efficient support of diverse traffic characteristics - RWS-120005
Efficient support for variety of traffic types - RWS-120010
Enhancements for variety of traffic types - RWS-120010
Very high traffic (and signalling) scenarios - RWS-120017
Control Plane Overhead Reduction - RWS-120021 / RWS-120046
Further Enhancements to Support Diverse Data Applications - RWS-120023
Efficiency : Small data services in high mobility - RWS-120024


User Experience
Improve User experience - RWS-120009
User Challenges - RWS-120032


Video streaming, call
RAN Enhancements for Video Streaming QoE - RWS-120023
RAN Enhancements for Internet Video Call - RWS-120023


WiFi / WLAN
Cooperation between LTE/HSPA and WiFi - RWS-120005
Unlicensed spectrum: LTE & WLAN - RWS-120007
LTE integration with other RATs - RWS-120014
WiFi integration: For Beyond Rel-12 - RWS-120017
LTE-WLAN Interworking - RWS-120023
Coordination With WiFi - RWS-120029
Smarter opportunistic usage of Wi-Fi - RWS-120031
LTE TDD Small-Cell versus WiFi - RWS-120041


Others
Other identified techniques for LTE - RWS-120005
Efficient Transactions - RWS-120035
Link Enhancement Considerations - RWS-120035
Intra-RAT cooperation / Inter-RAT cooperation - RWS-120036 / RWS-120050


Here is the summary from the workshop:

Complete list of Presentations

RWS-120002Release 12 and beyond for C^4 (Cost, Coverage, Coordination with small cells and Capacity)NSN
RWS-120003Views on Rel-12Ericsson & ST-Ericsson
RWS-120004LTE evolving towards Local Area in Release 12 and beyondNokia Corporation
RWS-120005Views on Release 12Orange
RWS-120006Views on Rel-12 and onwards for LTE and UMTSHuawei Technologies, HiSilicon
RWS-1200073GPP RAN Rel-12 & BeyondQualcomm
RWS-120008New Solutions for New Mobile Broadband ScenariosTelefonica
RWS-120009Telecom Italia requirements on 3GPP evolutionTelecom Italia
RWS-120010Requirements, Candidate Solutions & Technology Roadmap for LTE Rel-12 OnwardNTT DOCOMO, INC.
RWS-120011Where to improve Rel-12 and beyond: Promising technologiesNEC
RWS-120012Deutsche Telekom Requirements and Candidate TechnologiesDeutsche Telekom
RWS-120013Release 12 Prioritization ConceptsDish Networks
RWS-120014Towards LTE RAN EvolutionAlcatel-Lucent
RWS-120015UE AAS (Active Antenna System)Magnolia Broadband
RWS-120016Requirements and Technical Considerations for RAN Rel.12 & OnwardsFujitsu Limited
RWS-120017Operator requirements on future RAN functionalityTeliaSonera
RWS-120018AT&T View of Release 12 in the North America MarketplaceAT&T
RWS-120019Major drivers, requirements and technology proposals for LTE Rel-12 OnwardPanasonic
RWS-120020Efficient spectrum resource usage for next-generation N/WSK Telecom
RWS-120021Technologies for Rel-12 and onwardsSamsung Electronics
RWS-120022LTE Rel-12 and BeyondRenesas Mobile Europe
RWS-120023LTE Rel-12 and Beyond: Requirements and Technology ComponentsIntel
RWS-120024Considerations on further enhancement and evolution of UMTS/LTE network in R12 and onwardsChina Unicom
RWS-120025Views on LTE R12 and BeyondCATT
RWS-120026A proposal for potential technologies for Release 12 and onwardsETRI
RWS-120027A view on requirements on Rel-12 and onwards from an operator’s viewpointSoftbank Mobile
RWS-120028India market Requirements for Rel. 12 and beyondCEWiT
RWS-120029Views on LTE Rel-12 & BeyondCMCC
RWS-120030LTE addressing the needs of the Public Safety CommunityIPWireless
RWS-120031Vodafone view on 3GPP RAN Release 12 and beyondVodafone
RWS-120032An Operator’s View of Release 12 and BeyondSprint
RWS-120033Public Safety Requirements for Long Term Evolution REL-12U.S. Department of Commerce
RWS-120034Views on 3GPP Rel-12 and BeyondZTE
RWS-120035Considerations for LTE Rel-12 and beyondMotorola Mobility
RWS-120036LG’s view on evolution of LTE in Release 12 and beyondLG Electronics
RWS-120037Views on REL-12 and OnwardsChina Telecom
RWS-120038KDDI’s Views on LTE Release 12 onwardsKDDI
RWS-120039Evolving RAN Towards Rel-12 and BeyondSHARP
RWS-120040Views on enhancement of system capacity and energy efficiency toward Release12 and onwardHitachi
RWS-120041Beyond LTE-A: MediaTek’s view on R12MediaTek
RWS-120042Potential Technologies and Road Map for LTE Release 12 and BeyondITRI, HTC
RWS-120043New concept to maximize the benefit of interference rejection at the UE receiver: interference suppression subframes (ISS)Broadcom
RWS-120046Technologies for Rel-12 and onwardsSamsung Electronics
RWS-120047KDDI’s Views on LTE Release 12 onwardsKDDI
RWS-120048A view on Rel-12 and onwards from an operator’s viewpointSoftbank Mobile
RWS-120049UE AAS (Active Antenna System)Magnolia Broadband
RWS-120050LG’s view on evolution of LTE in Release 12 and beyondLG Electronics
RWS-120051New concept to maximize the benefit of interference rejection at the UE receiver: interference suppression subframes (ISS)Broadcom

More technically minded people want to explore the 3GPP website for the workshop links here: http://3gpp.org/ftp/workshop/2012-06-11_12_RAN_REL12/

Draft report that gives more insight into the presentations as follows:


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.

Saturday, 18 June 2011

Benefit of 1.4GHz for Mobile Downlink

Significant benefits could flow from use of 1.4 GHz band for a supplemental mobile downlink for enhanced multi-media and broadband services, according to a study by Plum Consulting conducted for Ericsson and Qualcomm.

The study by Plum Consulting shows that using the 1.4 GHz band (i.e. 1452-1492 MHz also called 1.5 GHz by the European Parliament or the L-band by the CEPT) for terrestrial supplemental mobile downlink could generate a net present value for Europe of as much as EUR54 billion over a 10 year period.

The band is currently allocated for use by digital audio broadcasting (DAB) services in most European countries -- part of the band is allocated to terrestrial networks and part is allocated to satellite networks. None of these services have developed in the band. Rather in all countries in Europe the satellite part of the band is unused and this is also the case in the terrestrial component in most countries.

There could be up to eight times as much data being downloaded than is being uploaded in mobile networks. This imbalance is expected to grow, as rich mobile content is increasingly made available and as consumer demand continues to soar. The study found that the use of the 1.4 GHz band as a supplemental downlink band for mobile applications is shown to drastically ease capacity, to enable considerably higher user data rates, to substantially enhance the user experience and to provide significant economic benefits.


The value of releasing the 1.4 GHz band depends on whether other substitute spectrum may become available in the next 5 to 10 years. Starting from today, all countries in Europe have planned or are planning to release the 800 MHz and 2.6 GHz bands in the next two years. There is equipment available for use in both bands and services are already deployed in some countries.

Which other bands might be released over the next 10-15 years? Table 3-2 gives a number of candidate bands, ordered by the likely timing for release, including the 1.4 GHz band for completeness. In each case, we summarise the current status of the band, initiatives that suggest it might be a candidate for future release and our views on the possible timing of deployment based on the difficulty of clearing the band and the harmonisation/standardisation initiatives that would need to be undertaken before equipment would be mass produced for the band.

The white paper is embedded below for reference:

Friday, 3 June 2011

Carrier Aggregation with a difference

Click on picture to enlarge

Another one from the LTE World Summit. This is from a presentation by Ariela Zeira of Interdigital.

What is being proposed is that Carrier Aggregation can use both the licensed as well as unlicensed bands but the signalling should only happen in the licensed band to keep the operator in control.

Note that this is only proposed for Small Cells / Femtocells.

The only concern that I have with this approach is that this may cause interference with the other devices using the same band (especially ISM band). So the WiFi may not work while the LTE device is aggregating this ISM band and the same goes for bluetooth.

Comments welcome!

Friday, 7 January 2011

LTE-Advanced (Rel-10) UE Categories

I blogged about the 1200Mbps of DL with LTE Advanced earlier and quite a few people asked me about the bandwidth, etc. I found another UE categories table in Agilent lterature on LTE-Advanced here.

The existing UE categories 1-5 for Release 8 and Release 9 are shown in Table 4. In order to accommodate LTE-Advanced capabilities, three new UE categories 6-8 have been defined.


Note that category 8 exceeds the requirements of IMT-Advanced by a considerable
margin.

Given the many possible combinations of layers and carrier aggregation, many configurations could be used to meet the data rates in Table 4. Tables 5 and 6 define the most probable cases for which performance requirements will be developed.

Monday, 20 December 2010

HSPA and LTE carrier aggregation

Last week there were press releases about the Long Term HSPA Evolution. The only thing that got reported mostly is the 650Mbps peak rates. There are other interesting features in Release-11 that is covered in Nokia Siemens Networks presentation. Here is one of them:

The idea of aggregating multiple carriers to increase performance is included in both LTE and HSPA. A logical step to fully leverage existing HSPA deployments and future LTE deployments is to aggregate the capacity of both systems and tie them together into a single mobile system. The concept is illustrated in Figure 3.

The aggregation of LTE and HSPA systems enables the peak data rates of the two systems to be added together. It also allows for optimal dynamic load balancing between the two radios. A small number of active LTE and HSPA aggregation-capable devices is sufficient to exploit this load balancing gain, since the network can schedule these devices to carry more data on the radio that has lower instantaneous loading and less data on the radio with the higher load at any given moment.

Carrier aggregation is expected to have no impact on the core network.


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.

Monday, 22 November 2010

Carrier aggregation deployment scenarios for Release-10 LTE-A

One of the important aspects to consider is that carrier aggregation should allow aggregation of not only the existing bands, but also bands that are introduced in future, e.g., 3.5 GHz band, etc. While existing bands already have certain deployments, new deployments can be considered for new bands that are introduced. Since introduction of new bands is done in a release independent fashion, considerations for such future bands are essential already in Rel-10. When higher frequencies such as 3.5 GHz are considered, path loss can be significant (e.g., 4-10 dB difference in link budget) when compared to 2 GHz. Hence, the most efficient deployment may not be to stick with the traditional macro-overlaying approach. Carrier aggregation should allow more flexible use of such new bands, since coverage and mobility can be ascertained by the existing band deployments, e.g., 2 GHz.

Picture below shows some of the potential deployment scenarios for carrier aggregation. Note that the scenarios listed are non-exhaustive. For example, other scenarios using repeaters and femto cells may be considered. Also note that F2 > F1.




Scenario 1
* F1 and F2 cells are co-located and overlaid, providing nearly the same coverage
* Both layers provide sufficient coverage and mobility can be supported on both layers.
* Likely scenario when F1 and F2 are of the same band, e.g., 2 GHz, 800 MHz, etc.
* It is expected that aggregation is possible between overlaid F1 and F2 cells.

Scenario 2
* F1 and F2 cells are co-located and overlaid, but F2 has smaller coverage due to larger path loss
* Only F1 provides sufficient coverage and F2 is used to provide throughput. Mobility is performed based on F1 coverage.
* Likely scenario when F1 and F2 are of different bands, e.g., F1 = {800 MHz, 2 GHz} and F2 = {3.5 GHz}, etc.
* It is expected that aggregation is possible between overlaid F1 and F2 cells.

Scenario 3
* F1 and F2 cells are co-located but F2 antennas are directed to the cell boundaries of F1 so that cell edge throughput is increased
* F1 provides sufficient coverage but F2 potentially has holes, e.g., due to larger path loss. Mobility is based on F1 coverage.
* Likely scenario when F1 and F2 are of different bands, e.g., F1 = {800 MHz, 2 GHz} and F2 = {3.5 GHz}, etc.
* It is expected that F1 and F2 cells of the same eNB can be aggregated where coverage overlap.

Scenario 4
* F1 provides macro coverage and on F2 Remote Radio Heads (RRHs) are used to provide throughput at hot spots
* Mobility is performed based on F1 coverage.
* Likely scenario when F1 and F2 are of different bands, e.g., F1 = {800 MHz, 2 GHz} and F2 = {3.5 GHz}, etc.
* It is expected that F2 RRE cells can be aggregated with the underlying F1 macro cells.

Scenario 5
* Similar to scenario #2, but frequency selective repeaters are deployed so that coverage is extended for one of the carrier frequencies

Scenarios supported in Rel-10 time frame
* For DL, all scenarios are supported in Rel-10
* For UL, scenario 4 and 5 are not supported in Rel-10

Source: R2-100531 CA deployment scenario NTT DOCOMO

Friday, 19 November 2010

CA (Carrier Aggregation) Scenarios in LTE-Advanced

CA (Carrier Aggregation) may be used in three different spectrum scenarios as follows.

Intraband Contiguous CA — This is where a contiguous bandwidth wider than 20 MHz is used for CA. Although this may be a less likely scenario given frequency allocations today, it can be common when new spectrum bands like 3.5 GHz are allocated in the future in various parts of the world. The spacing between center frequencies of contiguously aggregated CCs (Component Carriers) is a multiple of 300 kHz to be compatible with the 100 kHz frequency raster of Release 8/9 and preserving orthogonality of the subcarriers with 15 kHz spacing.

Intraband Non-Contiguous CA — This is where multiple CCs belonging to the same band are used in a non-contiguous manner. This scenario can be expected in countries where spectrum allocation is non-contiguous within a single band, when the middle carriers are loaded with other users, or when network sharing is considered.

Interband Non-Contiguous CA — This is where multiple CCs belonging to different bands (e.g., 2 GHz and 800 MHz are aggregated). With this type of aggregation, mobility robustness can potentially be improved by exploiting different radio propagation characteristics of different bands. This form of CA may also require additional complexity in the radio frequency (RF) front-end of UE. In LTE Release 10, for the UL the focus is on intraband CA, due to difficulties in defining RF requirements for simultaneous transmission on multiple CCs with large frequency separation, considering realistic device linearity. For the DL, however, both intra and interband cases are considered in Release 10, while specific RF requirements are being developed.

Text Source: Carrier Aggregation Framework in 3GPP LTE-Advanced - Mikio Iwamura et al. in IEEE Communications Magazine August 2010

Picture Source: http://www.catr.cn/tecm/dxwjs/201006/t20100610_1143968.htm

Friday, 27 February 2009

Dual-Cell HSPA in Release 8 and beyond

Some interesting developments are ongoing in the 3GPP standardisation from Release-8 onwards. You must be aware that the current bandwidth in UMTS/HSPA is 5 MHz. Since most of the operators generally won bigger chunk of spectrum of contiguous 5MHz band, they can actually combine these chunks to create a larger spectrum and hence increase data rates.

In Release 8 in downlink, it is possible to increase data rates using either a combination of MIMO and 64QAM or dual-cell HSDPA for operation on two 5MHz carriers with 64QAM, data rates reach up to 42Mbps.

In deployments where multiple downlink carriers are available, the new multicarrier operation offers an attractive way of increasing coverage for high bit rates. Rel-8 introduces dual-carrier operation in the downlink on adjacent carriers. This technique doubles the peak rate from 21Mbps to 42Mbps without the use of MIMO – it doubles the rate for users with typical bursty traffic; therefore, it also doubles the average user throughput, which translates into a substantial increase in cell capacity.

You may remember that I mentioned earlier that the operators are not too keen on going for MIMO for non-LTE technology. This is because they will have to upgrade their hardware and the antennas which could increase their cost significantly for a technology that is not going to be around for long.

Another thing to note before it becomes too confusing is that there are two terms for 'DC' being used right now. One of them is 'Dual Carrier' and other is 'Dual Cell'. In Release 8, the term being used is Dual-Cell for HSDPA which is also known as DC-HSDPA. The Technical specification to follow is 3GPP, TR 25.825 “Dual-Cell HSDPA operation” V1.0.0, May 2008.

The Dual-Cell assumes that both the 5MHz bands are contiguous. If they are not then the better term to refer for DC is Dual-Carrier.

A dual-carrier user can be scheduled in the primary serving cell as well as in a secondary serving cell over two parallel HS-DSCH transport channels. All non-HSDPA-related channels reside in the primary serving cell, and all physical layer procedures are essentially based on the primary serving cell. Either carrier can be configured to function as the primary serving cell for a particular user. As a consequence, the dual-carrier feature also facilitates an efficient load balancing between carriers in one sector. As with MIMO, the two transport channels perform hybrid automatic repeat request (HARQ) retransmissions, coding and modulation independently. A difference compared to MIMO is that the two transport blocks can be transmitted on their respective carriers using a different number of channelization codes. In terms of complexity, adding a dual-carrier receiver to UEs is roughly comparable to adding a MIMO receiver. Because the two 5MHz carriers are adjacent, they can be received using a single 10MHz radio receiver, which is already be available if the UE is LTE-capable.

Following the introduction in Release 8 of dual-carrier operation in the downlink, 3GPP is now discussing operation on multiple 5MHz carriers. Multiband operation of multiple carriers allows a single user to simultaneously aggregate and use the spectrum distributed over different bands. This gives operators greater fl exibility when using available spectrum. Increasing the number of carriers that UEs receive from two to four doubles the peak rate and achievable user throughput. For bursty traffic, this translates into substantially greater capacity, either as a larger number of users at a given data rate, or as a higher data rate for a given number of users. To substantially boost spectral effi ciency, 3GPP is studying the combination of dual-carrier operation and MIMO with 64QAM in the downlink, thereby doubling the peak data rate to 84Mbps. Similarly, they are studying the combination of MIMO, 64QAM and up to four downlink carriers to support peak data rates of more than 100Mbps. The support for UE reception on two frequency bands is an enabler to DC-HSDPA for operators who do not have adjacent 5MHz carriers available in one band, and is therefore of key importance for the further evolution of multi carrier HSPA.

As a consequence of increased data rates in downlink, the uplink data rates need to be improved too. From the aggregation of multiple FDD downlink carriers, the paired FDD uplink carriers can be utilized for improved uplink transmissions. 3GPP studies the usage of two adjacent 5MHz carriers for dual carrier uplink transmissions (DC-HSUPA) supporting data rates of up to 23Mbps. A further benefit of utilizing two uplink carriers is the possibility to support more efficient load balancing in the uplink direction.

In summary, uplink multicarrier operation increases availability as well as coverage of high data rates in the uplink.

In Conclusion, Rel-8 defines improvements in HSPA to achieve higher rates through dual carrier or combined 64QAM+MIMO operation. With the Rel-8 specification nearing completion (targeted for March 2009), planning is already under way in 3GPP for Rel-9 and Rel-10. Further multi-carrier and MIMO options are being explored for HSPA in Rel-9 and Rel-10

If you want to explore this topic further see: