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Showing posts with label IEEE. Show all posts
Showing posts with label IEEE. Show all posts

Monday, 3 June 2013

New Carrier Type (NCT) in Release-12 and Band 29

One of the changes being worked on and is already available in Release-11 is the Band 29. Band 29 is a special FDD band which only has a downlink component and no uplink component. The intention is that this band is available an an SCell (Secondary cell) in CA (Carrier Aggregation). 

What this means is that if this is only available as an SCell, any UE that is pre-Rel-11 should not try to use this band. It should not read the system information, reference information, etc. In fact the System Information serves little or no purpose as in CA, the PCell will provide the necessary information for this SCell when adding it using the RRC Reconfiguration message. This gives rise to what 3GPP terms as New Carrier Type for LTE as defined here. An IEEE paper published not long back is embedded below that also describes this feature in detail. 

The main thing to note from the IEEE paper is what they have shown as the unnecessary information being removed to make the carrier lean.

China Mobile, in their Rel-12 workshop presentation, have suggested 3 different types/possibilities for the NCT for what they call as LTE-Hi (Hi = Hotspot and Indoor).

Ericsson, in their Rel-12 whitepaper mention the following with regards to NCT:

Network energy efficiency is to a large extent an implementation issue. However, specific features of the LTE technical specifications may improve energy efficiency. This is especially true for higher-power macro sites, where a substantial part of the energy consumption of the cell site is directly or indirectly caused by the power amplifier.

The energy consumption of the power amplifiers currently available is far from proportional to the power-amplifier output power. On the contrary, the power amplifier consumes a non-negligible amount of energy even at low output power, for example when only limited control signaling is being transmitted within an “empty” cell.

Minimizing the transmission activity of such “always-on” signals is essential, as it allows base stations to turn off transmission circuitry when there is no data to transmit. Eliminating unnecessary transmissions also reduces interference, leading to improved data rates at low to medium load in both homogeneous as well as heterogeneous deployments.

A new carrier type is considered for Release 12 to address these issues. Part of the design has already taken place within 3GPP, with transmission of cell-specific reference signals being removed in four out of five sub frames. Network energy consumption can be further improved by enhancements to idle-mode support.

The IEEE paper I mentioned above is as follows:



Friday, 12 April 2013

Myths and Challenges in Future Wireless Access



Interesting article from the recent IEEE Comsoc magazine. Table 1 on page 5 is an interesting comparison of how different players reach the magical '1000x' capacity increase. Even though Huawei shows 100x, which may be more realistic, the industry is sticking with the 1000x figure. 

Qualcomm is touting a similar 1000x figure as I showed in a post earlier here.

Thursday, 31 January 2013

Tuesday, 8 May 2012

WiFi: Standards, Spectrum and Deployment

Yesterday, IEEE published its fourth revision to 802.11. The updates include faster throughput, improved cellular hand-offs, and better communication between vehicles in addition to other improvements.The following from IEEE website:

The new IEEE 802.11-2012 revision1 has been expanded significantly by supporting devices and networks that are faster, more secure, while offering improved Quality of Service and, improved cellular network hand-off. IEEE 802.11 standards, often referred to as “Wi-Fi®,” already underpin wireless networking applications around the world, such as wireless access to the Internet from offices, homes, airports, hotels, restaurants, trains and aircraft around the world. The standard’s relevance continues to expand with the emergence of new applications, such as the smart grid, which augments the facility for electricity generation, distribution, delivery and consumption with a two-way, end-to-end network for communications and control.

IEEE 802.11 defines one MAC and several PHY specifications for wireless connectivity for fixed, portable and mobile stations. IEEE 802.11-2012 is the fourth revision of the standard to be released since its initial publication in 1997. In addition to incorporating various technical updates and enhancements, IEEE 802.11-2012 consolidates 10 amendments to the base standard that were approved since IEEE 802.11’s last full revision, in 2007. IEEE 802.11n™, for example, defined MAC and PHY modifications to enable much higher throughputs, with a maximum of 600Mb/s; other amendments that have been incorporated into IEEE 802.11-2012 addressed direct-link setup, “fast roam,” radio resource measurement, operation in the 3650-3700MHz band, vehicular environments, mesh networking, security, broadcast/multicast and unicast data delivery, interworking with external networks and network management.

“The new IEEE 802.11 release is the product of an evolutionary process that has played out over five years and drawn on the expertise and efforts of hundreds of participants worldwide. More than 300 voters from a sweeping cross-section of global industry contributed to the new standard, which has roughly doubled in size since its last published revision,” said Bruce Kraemer, chair of the IEEE 802.11 working group. “Every day, about two million products that contain IEEE 802.11-based technology for wireless communications are shipped around the world. Continuous enhancement of the standard has helped drive technical innovation and global market growth. And work on the next generation of IEEE 802.11 already has commenced with a variety of project goals including extensions that will increase the data rate by a factor of 10, improve audio/video delivery, increase range and decrease power consumption.”

1 IEEE 802.11™-2012 “Standard for Information technology--Telecommunications and information exchange between systems Local and metropolitan area networks--Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications”


The following is from a presentation by Agilent in LTE World Summit last year. It summarises the 802.11 standards, the Spectrum available and deployment use cases.







Thursday, 12 April 2012

Whitespaces Standards


Continuing on the same topic of whitespaces from yesterday, we try and see who is working on the standardisation of whitespaces

IETF Protocol to Access White Space database (PAWS)

The charter for this WG was established 14 June 2011. Generally, the IETF strives to utilise established protocols rather than develop new ones. The objecives of this WG are:
  • Standardise a mechanism for discovering a white space database
  • Standardise a mechanism for accessing a white space database
  • Standardise query and response formats to be carried over the database access method
  • Ensure that the discovery mechanism, database access method and query response formats have appropriate security levels in place.
The WG goals are:
  • April 2012 Submit ‘Use-cases and Requirements for Accessing a Radio White Space Database’ to the IESG for publication as Informational. The current draft of this document is here: http://datatracker.ietf.org/doc/draft-ietf-paws-problem-stmt-usecases-rqmts/
  • December 2012, Submit ‘Accessing a Radio White Space Database’ to the IESG for publication as a Proposed Standard.

ETSI Reconfigurable Radio Systems (RRS)


The ETSI Technical Committee (TC) on Reconfigurable Radio Systems (RRS) has the responsibility for standardization activities related to Reconfigurable Radio Systems encompassing system solutions related to Software Defined Radio (SDR) and Cognitive Radio (CR), to collect and define the related Reconfigurable Radio Systems requirements from relevant stakeholders and to identify gaps, where existing ETSI standards do not fulfil the requirements, and suggest further standardization activities to fill those gaps.

IEEE Dynamic Spectrum Access Networks Standards Committee (DySPAN-SC)


The scope of the IEEE Dynamic Spectrum Access Networks Standards Committee (DySPAN-SC), which was formerly IEEE SCC41 until 2010, includes the following [1]:
  • dynamic spectrum access radio systems and networks with the focus on improved use of spectrum,
  • new techniques and methods of dynamic spectrum access including the management of radio transmission interference, and
  • coordination of wireless technologies including network management and information sharing amongst networks deploying different wireless technologies.
In December 2010 the IEEE SCC41 was re-organized as IEEE DySPAN-SC and its sponsor was changed from the IEEE Standards Coordinating Committee (SCC) to the IEEE Communications Society Standards Development Board (CSDB).
Included in the IEEE DySPAN SC are following working groups[1]:
  • 1900.1 Working Group on Definitions and Concepts for Dynamic Spectrum Access: Terminology Relating to Emerging Wireless Networks, System Functionality, and Spectrum Management
  • 1900.2 Working Group on Recommended Practice for Interference and Coexistence Analysis of In-Band and Adjacent Band Interference and Coexistence Between Radio Systems
  • 1900.4 Working Group on Architectural Building Blocks Enabling Network-Device Distributed Decision Making for Optimized Radio Resource Usage in Heterogeneous Wireless Access Networks
  • 1900.5 Working Group on Policy Language and Policy Architectures for Managing Cognitive Radio for Dynamic Spectrum Access Applications
  • 1900.6 Working Group on Spectrum Sensing Interfaces and Data Structures for Dynamic Spectrum Access and other Advanced Radio Communication Systems
  •  P1900.7 White Space Radio Working Group: Radio Interface for White Space Dynamic Spectrum Access Radio Systems Supporting Fixed and Mobile Operation
  • Ad hoc group on Dynamic Spectrum Access in Vehicular Environments (DSA-VE)
DySPAN SC is currently one of the most active standardization bodies for dynamic spectrum access radio systems and networks. 


CEPT/ECC WG Spectrum Engineering (SE), project team SE43

The ECC WGSE (Spectrum Engineering) has set up a special project dealing with cognitive radio matters. The SE43 was set up in May 2009 and finished its work in January 2011 by completing the ECC Report “Technical and Operational Requirements for the Possible Operation of Cognitive Radio Systems in the ‘White Spaces’ of the Frequency Band 470-790 MHz”The WG SE adopted the ECC Report 159 on white space devices for publication, in January 2011. This report can be downloaded from the undefinedCEPT/ECC website.

The main focus of the report is, as the title suggest, on coexistence with incumbent or primary systems. It contains definitions of “White Space”, cognitive radio and introduces the term “White Space Device” – WSD. The latter being the term used for the cognitive radio unit. The definition of “White Space” is taken from CEPT Report 24 “Technical considerations regarding harmonisation options for the Digital Dividend “ The report defines different scenarios for CR operation in terms of WSD types (personal/portable, home/office and public access points) and also discusses the three well known types of cognitive techniques: spectrum sensing, geo-location and beacons.
The report is focussed on protection of four possible incumbent systems: broadcast systems (BS), Program making and special events (PMSE), radio astronomy (RAS) and aeronautical radio navigation systems (ARNS). Comprehensive data on possible sensing and separation distances are given, and ends in operational and technical characteristics for white spaces devices to operate in the band. An estimate of available white space is also included.


Wightless


Weightless operates in an 8MHz-wide channel, to fit into the slots used for broadcast TV (and will thus have to squeeze into 6MHz if used across the pond where TV is smaller). Weightless is a Time Division Duplex (TDD) protocol, so access point and clients take turns to transmit.

When the hub device checks with the national database, it supplies a location and receives a list of 8MHz slots which aren't being used to transmit TV in that location. Weightless will hop between available slots every second or so, skipping any which turn out to be too cluttered (though periodically checking back in case they've cleared).

Showing its M2M roots, a Weightless access point only pages connected devices every 15 minutes, so those devices only need power up the radio four times an hour. Neul reckons that running the radio for two seconds at such intervals results in power consumption roughly equal to the decay rate of an idle battery, so being connected (and idle) has no perceivable impact on battery life.

That means a single Weightless hub can run connections to hundreds devices, across a network spanning 10km or so. Those devices could easily have a battery life measured in years, and be capable of responding with megabytes of data within 15 minutes.

A device which wants to connect to the network won't want to wait that long, and neither will one with something to report. In such circumstances the client can pick up a transmitted frame, which comes every second or two, and register an interest in sending some data upstream.

The security side of Weightless has yet to be worked out, with mutual authentication being considered more important than encrypting the content. Having someone listening in to a meter reading isn't that important, having someone faking a reading is, and content can always be encrypted at a higher level (Weightless will happily carry IPv4 and IPv6 packets).

Once on the network, a device has to wait for the hub to say when it can talk, though it has the chance to request communication slots. The speed of transmission is dependent on the quality of the signal. Each frame is addressed in a basically encoded header; all other devices can switch off their radios once they know the frame isn't addressed to them, and if the receiving device is nearby (as established by the signal strength) then the rest of the frame can be tightly encoded in the knowledge that little will be lost en route.

That means a Weightless hub can speak to hundreds of devices on the same network, with the speed of connection varying between devices. A receiver near the hub might therefore get 10Mb/sec or better, but one operating on the same network, from the same hub, could be running at a few hundred Kb in the same timeframe.


Thursday, 5 January 2012

IEEE standards impacting the future home


Interesting graphic from IEEE-SA depicting various IEEE standards impacting the home - via Steven Crowley on Twitter