From the 4G Americas presentation
Friday, 7 September 2012
Friday, 7 May 2010
Here is something from Cellular News today:
The European Commission has adopted a Decision establishing harmonised technical rules for Member States on the allocation of radio frequencies in the 800 MHz band that contribute to the deployment of high-speed wireless internet services by avoiding harmful interference.
In several Member States the 800 MHz frequencies are being freed up as part of the so-called "digital dividend" resulting from the switchover from analogue to digital television broadcasting. If Member States decide to change the existing frequency allocation (for broadcasting) they must immediately apply the harmonised technical rules laid down by the Decision to make these frequencies available to wireless broadband applications. Today's decision does not itself require Member States to make available the 790-862 MHz band for electronic communication services. However, the Commission is considering such a proposal in the forthcoming Radio Spectrum Policy Programme.
The Commission strongly supports the use of the 790-862 MHz band (currently used for broadcasting in most Member States) for electronic communication services and wants EU countries to act quickly, as coordinated management of this spectrum could give an economic boost of up to EUR44 billion to the EU's economy and help to achieve the EU 2020 Strategy target of high-speed broadband for all by the end of 2013 (with speeds gradually increasing up to 30 Mbts and above in 2020).
The new Commission Decision stipulates that all Member States which decide to make available the 790-862 MHz spectrum band (the so-called 800 MHz band) for services other than broadcasting should apply the same harmonised technical rules when they do so. These technical rules will ensure that radio communications equipment, like handsets or base stations using the 800 MHz band, can be used efficiently for wireless broadband networks, such as LTE or WiMAX.
Telecoms industry experts estimate that infrastructure to provide mobile broadband coverage using the 800 MHz band will be around 70% cheaper than through using the radio frequencies currently used by 3G networks. The lower costs involved in rolling out such networks will make these investments more attractive for operators, which should improve the geographic coverage of wireless broadband services. Application of the technical rules for frequency allocation foreseen by this Decision will substantially increase the potential economic benefits of the digital dividend by giving a new impetus to wireless internet services.
Until now, the 800 MHz band has been used for terrestrial TV broadcasting in most Member States. The new rules laid down in the Decision set out conditions for allocation of nearly one quarter of the frequencies that will become available when Member States switch from analogue to digital broadcasting (due by end 2012). The Commission is currently working on a Radio Spectrum Policy Programme that will take into account the other elements of the digital dividend and may also include a common date by which all Member States must make the 800 MHz band available.
Also read this post.
Wednesday, 21 April 2010
Monday, 19 April 2010
China's Ministry of Industry and Information Technology (MIIT), the carrier, handset and component makers, and handset solution suppliers in China in late 2008 began to cooperate for the development of TD-LTE in three phases, the report said.
The first-phase trial of technological concepts completed in June 2009, and the ongoing R&D and experiments in the second phase will be finished at the end of June 2010, the report indicated, adding the third phase will begin with China Mobile setting up three trial networks in the third quarter.
The trial network consists of 17 outdoor TD-LTE base stations made by Huawei Technologies completely covering the 5.28km square site and will be used to provide mobile high-definition multimedia services.
ZTE and Datang Mobile Communications Equipment as well as Motorola and Alcatel-Lucent have also set up TD-LTE access points inside a number of pavilions.
These milestones follow the announcement by China Mobile Communications Corporation (CMCC) in 2009, that Motorola was selected as main equipment supplier to provide indoor TD-LTE coverage for pavilions at Shanghai Expo. During the Shanghai Expo, Motorola will provide an advanced end-to-end TD-LTE solution and the world's first TD-LTE USB dongles. Motorola will also leverage its orthogonal frequency division multiplexing (OFDM) expertise with professional services to deploy, maintain and optimize these leading-edge networks. Visitors will be able to experience applications such as high-definition video on demand, remote monitoring and high-speed Internet access services.
Motorola, a leading provider of TD-LTE technology, and China Mobile share the same commitment to accelerating TD-LTE commercialization and globalization. "We are very excited to support China Mobile in bringing the world's first TD-LTE USB dongle demonstration enabled by our TD-LTE system," said Dr. Mohammad Akhtar, corporate vice president and general manager, Motorola Networks business in Asia Pacific. "A healthy devices ecosystem has always been critical to the development, commercialization and success of wireless network technologies. We are working closely with partners to drive this ecosystem as demonstrated by the advancement announced today. TD-LTE is now a commercial reality and we are very pleased to see that industry players are joining forces to accelerate TD-LTE globalization."
Interest in TD-LTE continues to grow because of several key factors: the low cost of TDD spectrum that is particularly attractive to emerging and developing markets; operators' continuing need for more capacity and spectrum; and the ability to hand-off between TD-LTE and LTE FDD networks. In effect, this ability to roam between LTE FDD and TD-LTE means operators can use TD-LTE networks to augment their FDD LTE network for more capacity or other applications such as video broadcasting, while operators choosing to use TD-LTE as their "main" network can still offer their subscribers the ability to roam to other operators' FDD LTE networks in different countries. Motorola is one of the few vendors in the industry that has expertise in, and is committed to investing in both FDD-LTE and TD-LTE, as well as WiMAX. By leveraging its orthogonal frequency division multiplexing (OFDM) expertise and WiMAX legacy, Motorola has built up its leadership position in TD-LTE with a number of industry-firsts.
"The development of terminals and devices has always been a bottleneck in the roll-out of new mobile technology," said Mr. Sha Yuejia, vice president of China Mobile. "We are thus more than happy to see that Nokia Siemens Networks has established a cutting-edge terminal testing environment, an initiative that we support wholeheartedly. After all, a healthy ecosystem needs efforts from all stakeholders."
Nokia Siemens Networks' Open Lab will provide an end-to-end testing environment for verifying the compatibility of terminals and devices with the company's TD-LTE network products and solutions. The lab will also provide consultancy and testing services to device manufacturers. Nokia Siemens Networks' TD-LTE R&D center in Hangzhou is fully integrated into the company's global network of LTE Centers of Competence.
Providing a live TD-LTE experience to operators in the region, Nokia Siemens Networks also recently kicked off a nationwide TD-LTE road show in China. Beginning in Beijing, the road show will cover more than ten provinces in three months, demonstrating the most advanced TD-LTE technology and applications.
US-based Qualcomm and Sweden's Ericcson aim to piggyback on TD-LTE, hoping that it will help them gain a toe-hold in India, the world's fastest growing mobile market. Qualcomm is to participate in the broadband wireless access (BWA) spectrum auction. If it does secure its bid in the auction, India could well become the first country after China to roll out TD-LTE.
TD-LTE, or Time Division Long Term Evolution, caters to peak download speeds of 100 Mbps on mobile phones, compared to the 20 Mbps for 3G and 40 Mbps for Wimax. LTE brings to the table additional spectrum, more capacity, lower cost, and is essential to take mobile broadband to the mass market.
The government has slotted the sale of two 2.3 GHz blocks of spectrum on April 11, providing 20 MHz spectrum in each of the country's 22 telecom circles. The base price has been set at $ 385 million. However, Qualcomm will need an Indian partner for its TD-LTE foray in the country since foreign direct investment is limited to 74%.
The US telco aims to use the 2.3 GHz spectrum band offered for TD-LTE-based BWA services. Sources in the know told TOI that the company would bid aggressively to corner one of the two BWA slots up for sale. There are 11 bidders for the BWA auction.
Asked to comment on the market dynamics, Sandeep Ladda, executive director, PricewaterhouseCoopers (PWC), said: "Though the Indian market is huge, it won't be smooth sailing post auction. We are adding 1 crore customers a month and in January, we added 1.9 crore customers, but the implementation of the new technology has its own cost. And India is a very cost conscious market."
Eager to play by the rules in India, Qualcomm has notified that it would enter into a joint venture with an Indian partner to launch its services and later exit from the joint venture after the network becomes operable.
Recently, the forum launched a global initiative to accelerate advanced WiMAX features that would double peak data rates and increase average and cell edge end user performance by 50 percent.
Mo Shakouri, vice president with the WiMAX Forum, said enhancements to the current generation of WiMAX weren't on the forum's roadmap, but were brought to the forefront at the urging of several WiMAX operators already facing capacity crunches. The forum reports that the average usage of data on WiMAX networks is close to 10 GB. Clearwire recently reported that mobile users average more than 7 GB of usage per month. In Russia, mobile WiMAX operator Yota sees more than 1 GB per month in data traffic from subscribers using its HTC smartphone. For laptops, it's 13 GB per month.
"Demand for data is moving so fast that we were pushed by many people to add this functionality," Shakouri said.
The WiMAX Forum has also been prodded to announce more detailed plans for 802.16m, and step up the timeline for its development via a new group called the WiMAX 2 Collaboration Initiative, which is made up of vendors Samsung, Alvarion, Motorola, ZTE, Sequans, Beceem, GCT Semiconductor and XRONet. The companies will work in tandem with the WiMAX Forum and WiMAX operators to accelerate the next-generation standard. WiMAX 2, the marketing name for the 802.16m standard, is expected to expand capacity to 300 Mbps peak rates via advances in antennas, channel stacking and frequency re-use.
The forum previously forecast 802.16m would hit in 2012 or 2013. But increasing demands for data--coupled with Qualcomm and Ericsson urging Indian mobile broadband license bidders to go with TD-LTE--motivated the forum to put some stakes in the ground and declare that WiMAX 2 equipment will meet certification by the end of 2011.
"There has been a lot of noise about TD-LTE, and the WiMAX Forum had not specifically given dates regarding timelines for 802.16m," Shakouri said. "Basically our announcement around 802.16m came about because of the noise in India."
The formation of the WiMAX 2 Collaboration Initiative is a marked change from the way the first generation of WiMAX was developed. Sprint Nextel was the entity driving the majority of the standards work as it was eager to get to market and begin building an ecosystem. Vendors are now taking the lead and driving equipment readiness before the 802.16m standard is finalized by the end of this year. Shakouri said the standard is 95 percent finished.
"Those companies are going to take a more active role inside the forum," Shakouri said. "They have all come together to speed up the process."
The group of vendors plans to collaborate on interoperability testing, performance benchmarking and application development before the WiMAX Forum establishes its certification program to narrow the gap between the finalized standard and commercial rollouts.
So how much of a threat is TD-LTE to WiMAX? Shakouri said the answer depends on spectrum decisions. "At this moment, the spectrum we are focusing on is separate, aside from what Qualcomm announced in India," Shakouri said. He also said that a TD-LTE ecosystem is at least two to three years behind WiMAX.
Many analysts speculate that TD-LTE will become the crossover technology that will prompt WiMAX operators to flip to LTE. Clearwire was part of a group of operators and vendors that last month asked the 3GPP standards body to begin working on specifications that would enable TD-LTE to be deployed in the 2.6 GHz band, which Clearwire uses for WiMAX. During the CTIA Wireless 2010 trade show last month, Clearwire CEO Bill Morrow reiterated the company's interest in deploying LTE when the technology catches up to WIMAX. He also called for one standard down the road.
Thursday, 17 December 2009
The current state of the mobile network environment such as public wireless LAN and the cellular phone lines and those problems were considered last time. This time, the focus is applied to “Mobility WiMAX” of the new service that solves these problems, and it introduces the difference with an existing mobile network. The 2nd explains the point of the IEEE standard by which the specification of mobile WiMAX has been decided.
Mobile WiMAX that the business service started in July, 2009 is a new mobile network that did “Cousin removing” of public wireless LAN and the cellular phone line. It becomes “Communication method of the world standard using the micro wave (frequency band of 3GHz-30GHz)” with WiMAX if it translates literally by the one that “World Interoperability for Microwave Access” was abbreviated.
It is a word “Communication (Access)” the hope of you attention here. “Line from the telephone office to the terminal” is indicated if it is said, “Access line” in the world on the network. In a word, WiMAX is a method to achieve the same role as the accomplishment of “[Furettsu] light” of ADSL and NTT on a wireless network.
Actually, there is details of having started WiMAX as a network for not the mobile network but fixed wireless telecommunications (FWA: Fixed Wireless Access). FWA is a method to send and receive data to the antenna set up in the rooftop in the communication tower and the building between terminals. FWA up to maximum transmission speed 156Mbps is an opening in Japan in December, 1998.
WiMAX is wireless MAN(Metropolitan Area Network) standard to achieve this FWA. Institute of Electrical and Electronic Engineers (IEEE) has approved WiMAX as “IEEE 802.16″ in December, 2001.
The bandwidth of 2GHz-11GHz was added back though WiMAX used the bandwidth of improving named 10GHz-66GHz at first. And, the specification named maximum transmission speed 134.4Mbps (occupation bandwidth 28MHz time) or 74.81Mbps (occupation bandwidth 20MHz time) was fixed by the maximum in “IEEE 802.16-2004″ that had been approved in June, 2004 communication distance 48km.
It has corresponded to the handover at 120km per hour.
It reaches up to 4.8km at the speed of 40Mbps or less.
Mobile WiMAX equipped in mobile PC is a wireless network method settled on as derivation standard “IEEE 802.16e” of IEEE 802.16.
Mobility WiMAX is that the maximum difference point of fixation WiMAX of IEEE 802.16 and mobile WiMAX corresponds to the handover (succession) that assumes the movable body of 120km per hour.
In a word, mobile WiMAX is to be able to use it in the train and the car running just like the cellular phone because a surrounding base station communicates one after another in “Hand over” according to the communication situation. There is especially no inconvenience if it thinks the communication distance of the cellular phone is several km though the maximum communication distance of mobile WiMAX is 4.8km and fixation WiMAX 1/10.
It differs according to the occupation bandwidth, and if it is 32Mbps, and it is 20MHz if it is 15Mbps, and 10MHz if the occupation bandwidth is 5MHz, the maximum transmission speed of mobile WiMAX is 75Mbps. In UQ communications that develop mobile WiMAX service domestically, it is sung, “It is 40Mbps or less, and is up-loading, and it is download and 10Mbps or less”. It may be expected that the same degree of the speed as wireless LAN in the office will be obtained as long as the condition is avoided.
Another difference between fixation WiMAX and mobile WiMAX is in the size of the terminal side transmitter-receiver. In fixation WiMAX where long distance/high speed has been achieved by a big transmission output, a considerably big as for terminal side device is needed. On the other hand, the transmitter-receiver of mobile WiMAX is being put in several LSI chips small. An external type is the same degree of the size as USB thumb drive.
Moreover, note PC with built-in controller for mobile WiMAX has been released by each vender since the summer of 2009. The “Let’snote S8/N8″ series of Panasonic especially supports WiMAX by the standard in the consumer model (A corporate model is for subject).
Another strong point is a base station. Wide, mobile WiMAX covers the range where the electric wave reaches and even if the number of base stations is not increased too much, can cover the large range at the cellular phone level. Because it is possible to communicate while it moves by in the train and car, it will be able to be said that it will be a very profitable network for the business user who frequently uses the Web application.
The maintenance of the base station is advanced in domestic various places with steady steps now. I hear that it became possible to use in the government-designated major city and major cities across the country at the end of fiscal year 2009 according to UQ communications.
Note, this is machine translation so ignore the errors.
Monday, 23 November 2009
Monday, 16 November 2009
Thursday, 5 November 2009
Continuing from yesterdays post.
The baseline WiMAX network architecture can be logically represented by a network reference model (NRM), which identifies key functional entities and reference points over which the network interoperability specifications are defined. The WiMAX NRM differentiates between network access providers (NAPs) and network service providers (NSPs). The NAP is a business entity that provides WiMAX radio access infrastructure, while the NSP is the business entity that provides IP connectivity and WiMAX services to WiMAX subscribers according to some negotiated service level agreements (SLAs) with one or more NAPs. The network architecture allows one NSP to have a relationship with multiple NAPs in one or different geographical locations. It also enables NAP sharing by multiple NSPs. In some cases the NSP may be the same business entity as the NAP.
The WiMAX NRM, as illustrated in Fig. 3, consists of several logical network entities: MSs, an access service network (ASN), and a connectivity service network (CSN), and their interactions through reference points R1–R8. Each MS, ASN, and CSN represents a logical grouping of functions as described in the following:
• Mobile station (MS): generalized user equipment set providing wireless connectivity between a single or multiple hosts and the WiMAX network. In this context the term MS is used more generically to refer to both mobile and fixed device terminals.
• Access service network (ASN): represents a complete set of network functions required to provide radio access to the MS. These functions include layer 2 connectivity with the MS according to IEEE 802.16 standards and WiMAX system profile, transfer of auathentication, authorization, and accounting (AAA) messages to the home NSP (HNSP), preferred NSP discovery and selection, relay functionality for establishing layer 3 (L3) connectivity with MS (i.e., IP address allocation), as well as radio resource management. To enable mobility, the ASN may also support ASN and CSN anchored mobility, paging and location management, and ASN-CSN tunneling.
• Connectivity service network (CSN): a set of network functions that provide IP connectivity services to WiMAX subscriber(s). The CSN may further comprises network elements such as routers, AAA proxy/ servers, home agent, and user databases as well as interworking gateways or enhanced broadcast services and location-based services.
A CSN may be deployed as part of a green field WiMAX NSP or part of an incumbent WiMAX NSP. The following are some of the key functions of the CSN:–IP address management–AAA proxy or server–QoS policy and admission control based on user subscription profiles–ASN-CSN tunneling support –Subscriber billing and interoperator settlement–Inter-CSN tunneling for roaming–CSN-anchored inter-ASN mobility–Connectivity to Internet and managed WiMAX services such as IP multimedia services (IMS), location-based services, peer-to-peer services, and broadcast and multicast services –Over-the-air activation and provisioning of WiMAX devices
• Base station (BS): a logical network entity that primarily consists of the radio related functions of an ASN interfacing with an MS over-the-air link according to MAC and PHY specifications in IEEE 802.16 specifications subject to applicable interpretations and parameters defined in the WiMAX Forum system profile. In this definition each BS is associated with one sector with one frequency assignment but may incorporate additional implementation-specific functions such as a DL and UL scheduler.
• ASN gateway (ASN-GW): a logical entity that represents an aggregation of centralized functions related to QoS, security, and mobility management for all the data connections served by its association with BSs through R6t. The ASN-GW also hosts functions related to IP layer interactions with the CSN through R3 as well as interactions with other ASNs through R4 in support of mobility.
Typically multiple BSs may be logically associated with an ASN. Also, a BS may be logically connected to more than one ASN-GW to allow load balancing and redundancy options. The WiMAX network specification defines a single decomposed ASN profile (ASN C) with an open R6 interface as well as an alternative ASN profile B that may be implemented as an integrated or a decomposed ASN in which R6 is proprietary or not exposed. The normative definitions of intra-ASN reference points (R6 and R8) are only applicable to profile C. Note that in release 1.5 profile A has been removed to reduce the number of implementation options and create a better framework for network interoperability.
Wednesday, 4 November 2009
The Mobile WiMAX Release 1.0 System Profile, based on 802.16e or 802.16-2005, was completed in late 2006, and the radio-level certification of products began in 2007. The certification follows a phased approach to address deployment priorities and vendor readiness. System Profile Release 1.0 includes all 802.16-2005 mandatory features, and also requires some of the optional features needed for enhanced mobility and QoS support. This system profile is based on OFDMA, and enables downlink and uplink multiple-input multipleoutput (MIMO) as well as beamforming (BF) features. The release 1.0 system profile is defined only for the TDD mode of operation, with more focus on 5 and 10 MHz bandwidths in several band classes in 2.3 GHz, 2.5 GHz ,and 3.5 GHz bands, but it also includes 8.75 MHz specifically for Korea.
The WiMAX certification for the release 1.0 profile started with a Wave 1 subset, excluding MIMO and a few optimization features, to enable early market deployments. This was followed by Wave 2, which progressively adds more and more feature tests over time based on vendors and testing tool availability. The early phases of certification were also limited to MAC and PHY layer conformance and interoperability testing, which will be expanded to add networklevel testing.
Meanwhile, the development of WiMAX Forum Network Release 1.0 was completed in 2007, based on which the specific network-level device conformance testing as well as infrastructure interoperability testing projects were initiated. The goal was to ensure e2e interoperability of WiMAX devices with networks and also ensure multivendor plug and play network infrastructure deployments. Release 1.0 defines the basic architecture for IP-based connectivity and services while supporting all levels of mobility. Based on operators’ requirements for advanced services and new market opportunities to be more competitive with evolved 3G systems, the WiMAX Forum initiated interim releases for both the system profile and network without major modifications to the IEE 802.16 standard. The work on network release 1.5 network specifications was started in parallel, aimed primarily at enabling dynamic QoS and provisioning of open retail device and support for advanced network services as well as commercial grade VoIP.
The release 1.5 system profile work item was initiated to enable mobile WiMAX in new spectrum including frequency-division duplex (FDD) bands, address a few MAC efficiency improvements needed for technology competitiveness, and align the system profile with advanced network services supported by network release 1.5. All required fixes and minor enhancements needed to support release 1.5 are incorporated in IEEE 802.16 REV2, which combines the IEEE 802.16-2004 base standard plus IEEE 802.16e/f/g amendments and related corrigenda into one specification document.
Following Release 1.5, the next major release mobile WiMAX, Release 2.0, will be based on the next generation of IEEE 802.16, which is being developed in the 16m technical group (TGm) of 802.16. WiMAX Release 2 targets major enhancements in spectrum efficiency, latency, and scalability of the access technology to wider bandwidths in challenging spectrum environments. Currently the expected timeline for the formal completion of 802.16m and WiMAX Certification of Release 2 products are early 2010 and early 2011, respectively.
In parallel with developments in IEEE on the stage 2 system-level description of 802.16m, the requirements for network release 2.0 are being discussed in the WiMAX Forum, where stage 2/3 specifications are expected to be completed by 2010.
Reference: Overview of Mobile WiMAX Technology and Evolution - Kamran Etemad, Intel Corporation
Tuesday, 20 October 2009
The 3GPP proposal for LTE-Advanced is here.
The IEEE proposal for 802.16m is here.
Thursday, 15 October 2009
We have mentioned about IMT-Advanced and LTE-Advanced before. International Mobile Telecommunications-Advanced is going to be the first 4G technology and as i discussed earlier, there are two main technologies vying for the 4G crown. I am sure both are as good and both will succeed. From 3GPP point of view, the standards will be part of Release-10 and should be ready end 2010 or beginning 2011. The understanding is that IMT-Advanced systems will support peak data rates of 100 Mb/s in high mobility environment (up to 350 km/h) and 1 Gb/s in stationary and pedestrian environments (up to 10 km/h). The transmission bandwidth of IMT-Advanced systems will be scalable and can change from 20 to 100 MHz, with downlink and uplink spectrum efficiencies in the ranges of [1.1, 15 b/s/Hz] and [0.7, 6.75 b/s/Hz], respectively. There will be a minimum requirement on voice over IP (VoIP) capacities in high- and low-mobility environments of around 30 and 50 active users/sector/MHz. The latency for control and user planes should be less than 100 ms and 10 ms, respectively, in unloaded conditions.
As I mentioned last week, the 3GPP candidate for IMT-Advanced is LTE-Advanced. On the IEEE front, 802.16j group published the relay-based multihop techniques for WiMAX and IEEE 802.16m has been submitted for the IMT-Advanced approval last week. The normal 802.16 WiMAX standard has been approved as 3G standard by the ITU.
So what exactly are Relays. Relay transmission can be seen as a kind of collaborative communications, in which a relay station (RS) helps to forward user information from neighboring user equipment (UE)/mobile station (MS) to a local eNode-B (eNB)/base station (BS). In doing this, an RS can effectively extend the signal and service coverage of an eNB and enhance the overall throughput performance of a wireless communication system. The performance of relay transmissions is greatly affected by the collaborative strategy, which includes the selection of relay types and relay partners (i.e., to decide when, how, and with whom to collaborate).
There are two different terminology used for Relay's. First is Type-I and Type-II and other is non-transparency and transparency. Specifically, a Type-I (or non-transparency) RS can help a remote UE unit, which is located far away from an eNB (or a BS), to access the eNB. So a Type-I RS needs to transmit the common reference signal and the control information for the eNB, and its main objective is to extend signal and service coverage. Type-I RSs mainly perform IP packet forwarding in the network layer (layer 3) and can make some contributions to the overall system capacity by enabling communication services and data transmissions for remote UE units. On the other hand, a Type-II (or transparency) RS can help a local UE unit, which is located within the coverage of an eNB (or a BS) and has a direct communication link with the eNB, to improve its service quality and link capacity. So a Type-II RS does not transmit the common reference signal or the control information, and its main objective is to increase the overall system capacity by achieving multipath diversity and transmission gains for local UE units.
Different relay transmission schemes have been proposed to establish two-hop communication between an eNB and a UE unit through an RS. Amplify and Forward — An RS receives the signal from the eNB (or UE) at the first phase. It amplifies this received signal and forwards it to the UE (or eNB) at the second phase. This Amplify and Forward (AF) scheme is very simple and has very short delay, but it also amplifies noise. Selective Decode and Forward — An RS decodes (channel decoding) the received signal from the eNB (UE) at the first phase. If the decoded data is correct using cyclic redundancy check (CRC), the RS will perform channel coding and forward the new signal to the UE (eNB) at the second phase. This DCF scheme can effectively avoid error propagation through the RS, but the processing delay is quite long. Demodulation and Forward — An RS demodulates the received signal from the eNB (UE) and makes a hard decision at the first phase (without decoding the received signal). It modulates and forwards the new signal to the UE (eNB) at the second phase. This Demodulation and Forward (DMF) scheme has the advantages of simple operation and low processing delay, but it cannot avoid error propagation due to the hard decisions made at the symbol level in phase one.
Friday, 9 October 2009
The 3GPP Partners, which unite more than 370 leading mobile technology companies, made a formal submission to the ITU yesterday, proposing that LTE Release 10 & beyond (LTE-Advanced) be evaluated as a candidate for IMT-Advanced. Complete press release here.
The IEEE today announced that it has submitted a candidate radio interface technology for IMT-Advanced standardization in the Radiocommunication Sector of the International Telecommunication Union (ITU-R).
The proposal is based on IEEE standards project 802.16m™, the “Advanced Air Interface” specification under development by the IEEE 802.16™ Working Group on Broadband Wireless Access. The proposal documents that it meets ITU-R’s challenging and stringent requirements in all four IMT-Advanced “environments”: Indoor, Microcellular, Urban, and High Speed. The proposal will be presented at the 3rd Workshop on IMT-Advanced in Dresden on 15 October in conjunction with a meeting of ITU-R Working Party 5D. Complete press release here.
Tuesday, 29 September 2009
There are all kinds of statistics about the number of Femtocells worldwide. There could be upto 70million by 2012. If this happens the big problem would be the interference between Macro and Femtocells and also between Femtos. OFDMA (used in LTE and WiMAX both) Femtocells can handle the interference better than CDMA (UMTS and CDMA2000) Femtocells due to its Intracell interference avoiding properties and robustness to multipath.
So what are the main problems that the operators will face when deploying femtocells? Lets look at some of them:
- Access method: Three different approaches exist namely, Open access, Closed access and Hybrid access which is a mix of both of them. The first two approach has some problems and I have suggested a solution before ;) but the best solution may be to go for Hybrid approach where limited connectivity is available to non-subscribers of the femto.
- Time Synchronisation is another important aspect of OFDMA Femtos. To minimise multi-access interference and for successful handovers, synchronisation between all the Femtos and between Femto and Macro is a must. This should be acheived without any complicated hardware so as to keep the cost down.
- Physical Cell Idendities (PCI) could be a problem because of limited numbers
- Neighbouring cell list, which is restricted to 32 in LTE, could be a problem if too many Femtos are around
- Handovers could also be a problem if the UE keeps jumping between Femtos and macro. One solution could be the use of HCS.
Interference analysis will definitelty play an important part in the rollouts. If not properly managed, could result in dead zones within Macro. Power control Algorithms and Radio Resource Management strategy will help but effective Spectrum allocation technique is needed as well. The diagram above shows different approaches for subchannel allocation in OFDMA femtocells.
The Femtocells would need to be self-configurable and self-optimising. I tried to explain the SON concept earlier which is similar. Self-configuration comes into picture when the Femto is switched on. Once the parameters are adjusted then Self-Optimisation tries to optimise these defaults into something better and more suited to the current environment. Sensing of the environment plays an important part in this. The diagram above shows different approaches being used by different Femtocells. The cheapest approach would ofcourse be the measurement report approach where the phone is made to report the environment. The only problem being that whichever phone was used (automatically selected) will have considerable amount of its battery power used up :)
There is a book that is under publication and will be available early next year. At the same time if it interests you, you can look at some of their publications including the IEEE one that has been quoted here. Here are all the necessary links:
- The Centre for Wireless Network Design
- Professor Jie Zhang homepage
- David López-Pérez, Research Fellow, homepage
- Femtocells World Summit presentation on Self-organisation of the Subchannel Assignment in OFDMA Femtocells
- OFDMA Femtocells: A Roadmap on Interference Avoidance - IEEE Communications magazine, Sep. 2009
- ICC 2009: Femtocells panel presentation slides
Hope someone finds all this info useful :)
Thursday, 17 September 2009
Thursday, 3 September 2009
Tuesday, 18 August 2009
MNP is not the only thing. Many operators and equipment manufacturers are waiting for the 3G spectrum auction for some time now. The auction was recently postponed for variety of reasons. The auction will let the private operators to bid for the spectrum and they can decide if they want 3G or WiMAX or LTE. The state run MTNL and BSNL have already launched 3G and in Northern India but there have been not many takers yet. Maybe the people are but sceptical right now or maybe the lack of devices. The other thing is that people are maybe not sure if the technology they invest in will be around tomorrow or not.
MTNL is keen to experiment with WiMAX but it does not want to do it alone. There are many companies in India that have developed WiMAX protocol stacks so it may be a boost for these generally small and medium sized companies if WiMAX is deployed by MTNL. The only problem with WiMAX is that there are hardly big global names with any WiMAX devices/equipment. As a reult the prices could be higher and the consumers may have less choice. 3G and LTE will help in this scenario. Qualcomm for example is already looking forward to getting a big chunck of the Indian market.
India has a very big pool of keen technologists and they will whole heartidly embrace mobile broadband and the variety of apps/mobiles but only when they know that there will be stability and reliability. Once the ball starts rolling then the snowball will turn into an avalanche. The question is not if, but when.
Tuesday, 7 July 2009
In the past two years, M2M (machine-to-machine) applications have become one of the most talked-about topics in the wireless industry. While M2M apps can be used for many purposes (such as smart homes, smart metering/electricity meter reading, fleet management, mobile workforce, automobile insurance and vending machines) and in many sectors (such as healthcare, agriculture, commercial, industrial, retail and utility), smart metering applications--also known as smart grids--present the biggest growth potential in the M2M market today. With many leading wireless service providers and utility companies jumping on the bandwagon and the growing support from states like Texas and California, M2M applications are set to become very successful in the coming years.
AT&T in March announced a new alternative for electric utility companies looking to provide the benefits of smart grid technology to the residential sector. AT&T and SmartSynch are for the first time providing utilities with a cost-effective solution by combining a new suite of service plans from AT&T designed specifically for machine to machine (M2M) communications with SmartSynch's smart grid solutions already deployed at more than 100 utilities throughout North America.
With this new solution from AT&T and SmartSynch, electric utility companies will now be able to concentrate on efficient electricity delivery rather than being distracted by building, maintaining, expanding and upgrading a communications network. This new solution offers a cost-effective point-to-point configuration model in which each meter communicates directly with the utility over the AT&T wireless network.
Smart grids combine "smart meters", wireless technology, sensors and software so customers and utilities can closely monitor energy use and cut back when the availability of electricity is stretched to its limit. The IP-based smart grid model ultimately helps consumers understand the economics of their consumption patterns so they can make intelligent decisions about their power consumption. The smart grid technology will also help to enhance reliability and energy efficiency, lower power-line losses and provide utilities with the ability to remotely automate service, providing cost-savings for consumers.
Key benefits of the point to point smart meter solution to utility companies include:
- improved speed of deployment over traditional meshed networks
- the simplicity of an open standard, IP-based network
- the ability to communicate directly with each meter.
How can T-Mobile, the fourth-largest cell phone carrier in the U.S., generate business in the face of dropping net additional subscribers and competition from low-cost cell phone companies? Get into the smart grid. Like AT&T and Verizon, T-Mobile is hoping to leverage its already built-out wireless networks to tap into the coming smart grid boom spurred by the stimulus package. On Thursday, T-Mobile plans to announce that it’s developing a durable SIM card that can be embedded in smart meters (as well as used for other industrial processes), and a new partnership with smart meter technology maker Echelon.
Mobile’s national director of Machine-to-Machine services, John Horn, told us that T-Mobile has been playing in the connected electric meter space for several years, including working with smart meter maker SmartSynch (AT&T has a deal with them, too), and he says the carrier has several utility pilot projects under way in the Pacific, Southwest and Midatlantic regions with an aggregate of “tens of millions” of smart meters. In some of those trials T-Mobile has been testing out its new smart meter SIM card, which is like the SIM card in your regular cell phone, but smaller — 5 by 6 millimeters — more durable and made of silicon, not plastic. Horn says the SIM, which can be connected to any of T-Mobile’s wireless networks, including 3G, can withstand the heat and environmental conditions of being outdoors in a smart meter much better than a standard SIM card.
One of the first smart meter makers to embed the new SIM is Echelon, which is also working with T-Mobile on a smart meter service that will run over T-Mobile’s wireless networks and, according to the companies, is significantly cheaper for utility customers. T-Mobile is just the latest phone company to drop its prices to attract utilities. AT&T and SmartSynch announced a similar deal last week. Horn said of T-Mobile’s smart grid price move: “We’ve broken historical pricing models.”
Network technologies including LTE, mobile WiMAX, WiFi and ZigBee potentially could be used for future smart grid applications. While it is still too soon to tell which technology is likely to become the big winner in this market, mobile WiMAX appears to have an edge over LTE due to mobile WiMAX's time-to-market advantage. Mobile WiMAX also has the advantage of being more reliable and secure than "pure" unlicensed technologies like WiFi. WiMAX can also count on support from leading companies like GE, Intel, Sprint Nextel, Clearwire, Motorola, Samsung and Google, among others.
Most importantly, WiMAX will enable carriers, utility companies and other key players to build open-standards based smart meters. Ultimately, through WiMAX, third parties will be able to develop many applications and devices, helping to reduce cost. With WiMAX chipsets currently running about $36, some observers believe that the cost could become as low as $8 or $6 in the next 18 months.
In the meantime, WiMAX-based smart meters are already available in the U.S. For instance, GE, in association with Intel and Grid Net software, has built one of the first WiMAX-based smart meters. Intel Capital and GE both invested in Grid Net in 2006. Companies competing with GE include companies like Trilliant, Itron, Silver Spring Networks (also one of GE's partners) and Landis & Gyr.
However, over time, LTE could become a valuable option for many companies involved in this space as LTE becomes widely adopted and prices associated with it start to come down. LTE's larger coverage capacity and ability to support a higher number of points should play a key role here. In our opinion, it will also become critical for LTE carriers to offer a decent revenue share with utility companies and other key players.
Although being a short-range technology, ZigBee could also have a role to play in the M2M apps space as several companies have expressed some interest in the technology. In fact, U.S.-based startup Tendril Networks is well positioned to become a pioneer in this space; the company, which teamed up with Itron and Landis & Gyr, has already developed a product called Tendril Residential Energy Ecosystem (TREE), compatible with various ZigBee-based devices to be used for smart grid apps inside homes.
Lastly, if fully secured, WiFi could also become a disruptor. WiFi-based smart grid apps appear to be gaining traction in the U.S. and Europe. For instance, the city of San Jose, in association with Echelon, is currently testing a whole smart streetlight network using WiFi-based smart grids set to be launched this summer. The system may receive federal stimulus money, and if it does the city plans to revamp the entire 65,000-light network, which would help reduce energy costs by 40 percent. That figure is consistent with the performance of two European cities: Milton Keynes in the United Kingdom and Olso in Norway, which have been implemented by Echelon.
From Ajit Jaokar's Open Gardens Blog:
While Telcos have historically rebelled against 'opening up', the US administration's emphasis on Open is creating huge opportunities for Telecoms and the Cloud
Broadband stimulus grants are tied to net neutrality rules, which means networks have to allow users to connect any device to the network
But this also leads to a huge opportunity because now Telecoms can extend their reach into the Smart Grid through MTM (machine to machine) applications which will generate a much higher number of network connections. These may have less ARPU (i.e. average revenue per user) but a greater number of actual connections with no need to subsidise devices. Hence, they could be profitable.
A smart grid starts with a 'smart meter' which is capable of two way communications and lets the user and provider manage electricity consumption in a more granular way. If the customer's power consumption can be captured in a granular manner, the provider can offer specials/ discounts to the customer. The added potential of smart grids arises from knowing data trends and also extend power management to other devices. These synergies fit well into LTE and home gateways and this explains with LTE and also explains Verizon's emphasis on Ipv6
The Verizon Itron partnership is an example of such a service and this service will be a part of Verizon's LTE deployment in the 700 MHz band for M2M apps.
The Zigbe alliance is also gaining traction as a result of this move by building wireless intelligence and capabilities into everyday devices and all this will lead to the 50 billion devices mark which suddenly does not sound so far away
On the services side, initiatives like Microsoft Hohm are being deployed and even if a utility isn't a part of Hohm, users can enter data directly which means that they can get more benefits the more they contribute to it.Google power meter is a similar initiative from Google.
Thus, Smart grids, LTE and the Cloud are a huge opportunity for the industry - but the privacy concerns with sensor networks and the Cloud will play an important part here.
Companies are building out the smart grid with various broadband technologies — cellular, WiFi, WiMAX — so why not good ol’ DSL? Smart grid sensor and software maker Current is touting a new smart grid partnership with DSL provider Qwest.
Current largely provides the sensors that monitor different conditions on the electrical network, like voltage and current, as well as the software that processes the sensor information for the utility customer. While Current is mostly focused on the distribution portion of the grid, it can also provide communication gear and sensors for smart meters and in-home gateways, which it is doing for Colorado utility Xcel Energy for its SmartGridCity rollout. Because Current needs to get its information back to the utility, it works with a number of companies that provide that network connection. The latest is Qwest, which Current started partnering with, and is currently working with, for Xcel Energy’s SmartGridCity plan (Qwest provides phone and broadband service in Colorado). The buildout of SmartGridCity is supposed to be completed soon, followed by an assessment of the network’s benefits.
What are the benefits of using DSL? Current’s senior vice president of business solutions, Mae Squier-Dow, says that because DSL is already widely available, using it speeds up the ability to deploy smart grid technology. And because the networks have already been built, she says, the option is more affordable for a utility than building out its own communications network. (Other companies argue that in the long run it’s cheaper to build and own the network). Since DSL is a proven technology, it can help smart grid projects gain access to stimulus funds meant for “shovel-ready” projects, Squier-Dow says.
DSL is also high-speed, so if utilities want to use the networks for more bandwidth-intensive services, they can. And DSL is based on Internet Protocol, so it can more easily connect with other IP-based networks and systems, which are ubiquitous. Ultimately DSL is a standard that’s been used for years, so utilities can be rest assured that the technology is highly reliable.