Available to download from here.

Available to download from here.

Was listening to the Softbank webcast earlier about why they are so happy on receiving the 900MHz spectrum. The extract from slidepack summarises the advantages on this ‘Platinum Band’

A Video presentation of the above is embedded below:

PDF of the above presentation is available here.

A video of the actual presentation is embedded below. Its quite long (94 minutes)

The presentation is available to download in PDF format from here.

The presentation is available to download from here.

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)

• 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.

• 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)

• 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.

• 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)

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 CEPT/ECC website.

Wightless

BT has been conducting a “White Space” trial in Isle of Bute, UK. Initial report suggests that the results are not very impressive. The following is from ISP Review: 

Early feedback from BT’s trial of ‘White Space‘ (IEEE 802.22) wireless broadband technology on the Isle of Bute suggests that the service, which delivers internet access by making use of the unused radio spectrum that exists between Digital TV channels, still has a lot of problems to overcome, not least in terms of its sporadic performance.

In theory the 802.22 specification suggests that download speeds of up to 22Mbps per channel (Megabits per second) could be possible and some UK trials claim to have reached around 16Mbps, which is incidentally a long way off the UK’s chosen definition for superfast broadband (24Mbps+).

But separate reports from both PC Pro and the BBC today found that the service, which is complicated to deliver due to the ever changing spectrum and the risk of causing interference to DTV services, could struggle to deliver its top speeds.

At present BT’s implementation claims to be offering speeds of up to 10Mbps per channel, which will soon be upgraded to 15Mbps, but this reduces down to a maximum of just 4Mbps when 6km away from the transmitter. New tests at various points on the Isle of Bute showed speeds varying between just 1.5Mbps and 6Mbps (the latter was recorded within sight of BT’s mast).
In fairness White Space solutions are designed to target the last 10% of the UK where the government has so far only committed to a minimum download speed of just 2Mbps for all (Universal Service Commitment), which is a very low target. In addition White Space tech appears to deliver strong upload speed that is, in some cases, symmetrical. That makes it good for video conferencing and other upload dependent tasks.

As Fierce Broadband Wireless suggests, the low speeds could also be due to pre-standard gear that will just improve as time goes on.

The main reason for using this shared whitespace spectrum is due to the fact that the total amount of spectrum is limited and we want to make use of every available free spectrum to increase capacity of the overloaded networks.

Michael Fitch from BT recently spoke in our Cambridge Wireless Small Cells SIG event. The slide from his presentations neatly lays out the vision for shared spectrum.

In theory, even though this looks simple, in practice managing the database is a challenge by itself. The embedded slides below (Page 17 onwards) show the problems and the complexity associated with the database.

Spectrum sharing issues for small cells

View more presentations from Zahid Ghadialy

Time will tell how efficient and practical using whitespaces is.

A layer 1 relay consists of relay technology called a booster or repeater. This is an Amplifier and Forward (AF) type of relay  technology by which Radio Frequency (RF) signals received on the downlink from the base station are amplified and transmitted to the mobile station. In a similar manner, RF signals received on the uplink from the mobile station are amplified and transmitted to the base station. The equipment functions of a layer 1 relay are relatively simple, which makes for low-cost implementation and short processing delays associated with relaying. With these  features, the layer 1 relay has already found widespread use in 2G and 3G mobile communication systems. It is being deployed with the aim of improving coverage in mountainous regions, sparsely populated areas and urban areas as well as in indoor environments.


The RF performance specifications for repeaters have already been specified in LTE, and deployment of these repeaters for the same purpose is expected. The layer 1 relay, however, amplifies intercell interference and noise together with desired signal components thereby deteriorating the received Signal to Interference plus Noise power Ratio (SINR) and reducing the throughput enhancement gain.


The layer 2 relay, meanwhile, is a Decode and Forward (DF) type of relay technology by which RF signals received on the downlink from the base station are demodulated and decoded and then encoded and modulated again before being sent on to the mobile station. This demodulation and decoding processing performed at the radio relay station overcomes the drawback in layer 1 relays of deteriorated received SINR caused by amplification of intercell interference and noise. A better throughput-enhancement effect can therefore be expected compared with the layer 1 relay. At the same time, the layer 2 relay causes a delay associated with modulation/demodulation and encoding/decoding processing. In this type of relay, moreover, radio functions other than modulation/demodulation and encoding/decoding (such as mobility control, retransmission control by Automatic Repeat request (ARQ), and user-data concatenation/segmentation/reassembly) are performed between the base station and mobile station transparently with respect to the radio relay, which means that new radio-control functions for supporting this relay technology are needed. 

The layer 3 relay also performs demodulation and decoding of RF signals received on the downlink from the base station, but then goes on to perform processing (such as ciphering and user-data concatenation/segmentation/reassembly) for retransmitting user data on a radio interface and finally performs encoding/modulation and transmission to the mobile station. Similar to the layer 2 relay, the layer 3 relay can improve throughput by eliminating inter-cell interference and noise, and additionally, by incorporating the same functions as a base station, it can have small impact on the standard specifications for radio relay technology and on implementation. Its drawback, however, is the delay caused by user-data processing in addition to the delay caused by modulation/demodulation and encoding/decoding processing.


In 3GPP, it has been agreed to standardize specifications for layer 3 relay technology in LTE Rel. 10 because of the above features of improved received SINR due to noise elimination, ease of coordinating standard specifications, and ease of implementing the technology. Standardization of this technology is now moving forward.


Layer 3 radio relay technology is shown in Figure 2. In addition to performing user-data regeneration processing and modulation/demodulation and encoding/ decoding processing as described above, the layer 3 relay station also features a unique Physical Cell ID (PCI) on the physical layer different than that of the base station. In this way, a mobile station can recognize that a cell provided by a relay station differs from a cell provided by a base station.


In addition, as physical layer control signals such as Channel Quality Indicator (CQI) and Hybrid ARQ (HARQ) can terminate at a relay station, a relay station is recognized as a base station from the viewpoint of a mobile station. It is therefore possible for a mobile station having only LTE functions (for example, a mobile station conforming to LTE Rel. 8 specifications) to connect to a relay station. Here, the wireless backhaul link (Un) between the base station and relay station and the radio access link (Uu) between the relay station and mobile station may operate on different frequencies or on the same frequency. In the latter case, if transmit and receive processing are performed simultaneously at the relay station, transmit signals will cause interference with the relay station’s receiver by coupling as long as sufficient isolation is not provided between the transmit and receive circuits. Thus, when operating on the same frequency, the wireless backhaul-link and radio-access-link radio resources should be subjected to Time Division Multiplexing (TDM) so that transmission and reception in the relay station are not performed simultaneously.

Scenarios in which the introduction of relay technology is potentially useful have been discussed in 3GPP. Deployment scenarios are shown in Table 1. Extending the coverage area to mountainous and sparsely populated regions (rural area and wireless backhaul scenarios) is an important scenario to operators. It is expected that relay technology can be used to economically extend coverage to such areas as opposed to deploying fixed-line backhaul links. Relay technology should also be effective for providing temporary coverage when earthquakes or other disasters strike or when major events are being held (emergency or temporary coverage scenario), i.e., for situations in which the deployment of dedicated fixed-line backhaul links is difficult. In addition, while pico base stations and femtocells can be used for urban hot spot, dead spot, and indoor hot spot scenarios, the installation of utility poles, laying of cables inside buildings, etc. can be difficult in some countries and regions, which means that the application of relay technology can also be effective for urban scenarios. Finally, the group mobility scenario in which relay stations are installed on vehicles like trains and buses to reduce the volume of control signals from moving mobile stations is also being proposed.


In 3GPP, it has been agreed to standardize the relay technology deployed for coverage extension in LTE Rel. 10. These specifications will, in particular, support one-hop relay technology in which the position of the relay station is fixed and the radio access link between the base station and mobile station is relayed by one relay station.

References
[1] 3GPP TS36.912 V9.1.0: “Feasibility study for Further Advancement for E-UTRA (LTE-Advanced),” 2010.
[2] 3GPP TS36.323 V9.0.0: “Evolved Universal Terrestrial Radio Access (E-UTRA); Packet Data Convergence Protocol (PDCP) specification,” 2009
[3] 3GPP TS36.322 V9.1.0: “Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Link Control (RLC) protocol specification,” 2010.
[4] 3GPP TS36.321 V9.2.0: “Evolved Universal Terrestrial Radio Access (E-UTRA); Medium Access Control (MAC) protocol specification,” 2010.
[5] 3GPP TS36.331 V9.2.0: “Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource Control (RRC); Protocol specification,” 2010.
[6] 3GPP TS36.413 V9.2.1: “Evolved Universal Terrestrial Radio Access (E-UTRA); S1 Application Protocol (S1AP),” 2010.
[7] 3GPP TR36.806 V9.0.0: “Evolved Universal Terrestrial Radio Access (E-UTRA); Relay architectures for E-UTRA (LTEAdvanced),” 2010.
[8] IETF RFC4960: “Stream Control Transmission Protocol,” 2007.
[9] 3GPP TS29.281 V9.2.0: “General Packet Radio System (GPRS) Tunnelling Protocol User Plane (GTPv1-U),” 2010.