TDD-LTE Sasktel "Experiment"

[oneoff]

SaskTel to test LTE in rural areas
By: Howard Solomon On: 10 Sep 2012 For: ComputerWorld Canada



Carrier to try fixed wireless version of the technology to bring high speed broadband to outlying areas




One of the problems bedevilling carriers is how to deliver faster broadband speeds to rural customers as they boast about the speeds their urban clients can get.

SaskTel said Monday it will test a new approach starting in December in three Saskatchewan communities: Fixed data and voice wireless service using the LTE standard.

The carrier announced from Bejing that it has signed an agreement with Huawei Technologies for a nine-month trial to see if the technology is economically feasible.

The pact was announced in China in part because Premier Brad Wall is there on a mission.





(SaskTel CEO Ron Styles and Huawei Canadea president Sean Yang at signing ceremony in Bejing.)
“SaskTel's copper infrastructure dates back to the 1960s and we are fast approaching the need to replace and upgrade this technology," SaskTel CEO Ron Styles said in a statement. "With the positive partnership that has evolved with Huawei with our 4G network and our mobile LTE wireless deployment efforts that are underway, we are very pleased to partner with them to complete this trial."

LTE, short for Long-Term Evolution, is usually thought of a mobile wireless data technology built into the latest handsets, tablets and USB modems.

This test will use Huawei base stations and customer modems using technology called TDD-LTE (for time-division duplex), a version developed by Chinese telecom manufacturers like Huawei which doesn't require paired spectrum. Transmit and receive signals are sent on the same channel. Handsets in North America use FDD-LTE (for frequency-division duplex), which requires paired spectrum. The test will use SaskTel’s spectrum in the 2.5 GHz band. Also to be tested is the suitability of the emerging voice-over-LTE (VoLTE) technology. LTE handsets now still carry voice signals over a separate band. VoLTE is a converged Internet protocol voice-data technology that promises carriers greater efficiencies with their spectrum.




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Scott Bradley, vice-president of government and corporate affairs for Huawei Canada, who is in Bejing for the deal signing, said in a phone call this morning that the trial will test the speed and range of the technology, as well as different residential modem/antenna options. Extending broadband into Saskatchewan's less densely-populated areas is a problem because some homes are several kilometers away from each other, he said.


Huawei is doing similar tests in several countries, he said, including Portual. He didn't have details on how they are going. This is new technology for Huawei, he said, that has started rolling out only in the last six months.

[oneoff]

This might be a little more information than most people can/will handle but maybe your completely necessary future rural communication needs will be founded on what is explained below.
Remember Brad Wall signed on for TDD and not FDD. I hope he knows the difference, and especially hope it works..

What is TDD?

There are two modes of operation for LTE technology: FDD and TDD, which are technically very similar and part of the same radio access specification. LTE FDD and TDD were both defined and introduced as part of the 3GPP specification in 2009 to make efficient use of paired and unpaired spectrum allocations over a common, core network architecture. The main differences are around the duplex method used.




In both LTE FDD and LTE TDD, the transmitted signal is organized into subframes of one millisecond (ms) duration and 10 subframes constitute a radio frame. Each subframe normally consists of 14 orthogonal frequency division multiplexing (OFDM) symbols (12 OFDM symbols in an extended cyclic prefix). Although the frame structure is, in most respects, the same for LTE FDD and LTE TDD, there are some differences between the two—most notably the use of special subframes in TDD. The subframes in TDD are allocated either for uplink (UL) or downlink (DL) transmission.




In the case of FDD operation, there are two carrier frequencies, one for UL transmission and one for DL transmission. During each frame, there are consequently 10 UL subframes and 10 DL subframes, and UL and DL transmission can occur simultaneously within a cell.




In TDD operation, there is only a single carrier frequency, and UL and DL transmissions in the cell are always separated in time. As the same carrier frequency is used for UL and DL transmission, both the base station and the mobile terminals must switch from transmission to reception and vice versa. Thus, as a subframe is either a UL subframe or DL subframe, the number of subframes per radio frame in each direction is less than 10.





Figure 2. FDD can cover a larger area with the fixed DL/UL on different frequencies, but TDD can provide more DL capacity with the flexible DL/UL ratio2.



LTE TDD’s relationship to FDD

TDD makes it relatively easy to dynamically change the capacity ratio between UL and DL to reallocate time slots, which makes it well suited for today’s DL-heavy traffic pattern. In most instances, network operators will desire more DL capacity than UL since users more frequently download content like video and web pages than upload content they’ve created.




Beyond the regional deployments of TD-SCDMA, TDD wasn’t deployed widely in 3G networks, but it has great potential in LTE. The operator community was originally hesitant to adopt this new technology due to its similarity to WiMAX, but has since discovered that TDD and FDD technologies can co-exist nicely and is now supportive of a new market with TDD LTE. Because they have common core network architecture, there is no additional CAPEX and the two technologies interoperate seamlessly. The main difference is the need for a specific radio frequency (RF) unit. Another significant difference is in the physical layer definition; the higher layers and the rest of network architecture remain applicable for FDD.




FDD is still leading the game, however. Most commercial LTE networks are based on FDD because the FDD ecosystem is more mature and is still where most of the spectrum allocation is done. All major operators around the world are already acquiring wide bands of FDD spectrum for their 4G LTE networks, which is well suited for voice because it is inherently symmetric in the UL and DL. In addition, FDD can provide better coverage of a larger area due to the fixed DL/UL on different frequencies.




However, some operators are able to exploit the TDD advantage by deploying the two technologies in tandem to offload traffic for very asymmetrical applications such as video or even newer areas like machine-to-machine (M2M) applications. For example, Vodafone has developed an innovative use case of LTE TDD being used as a backhaul for small cell deployments. As multimedia broadcast and multicast services (MBMS) pick up traction, it makes even more sense to effectively deliver this broadcast information in the DL using the unpaired TDD without impacting the user services delivered on FDD in parallel.




Existing FDD networks can leverage LTE TDD for targeted capacity expansions, ensuring a larger economy of scale by utilizing common EPC network architecture wherever possible. TDD is excellent for hot-spot expansions (picocells and femtocells) and new LTE TDD networks plan for small nodes from day one. LTE TDD is an excellent indoor complement for small nodes because it does not interfere with the FDD network. It is the ideal technology to leverage unpaired spectrum, which is typically available at higher frequency bands optimal for capacity expansion, making it less fragmented. Most FDD deployments use 2.6GHz, but some of the largest rollouts used other bands. The risk associated with a technology deployed in many different spectrum bands is that its adoption is hindered because manufacturers will not create as many devices to support it. TDD is in a much better position since most of the rollouts are expected in only two frequency bands: 2.3GHz and 2.6GHz. Chipset manufacturers are especially interested in 2.3GHz deployments for well-populated countries. TDD also enables a number of smart-antenna technologies such as beamforming. A mix of LTE TDD hot-spots with LTE FDD macrocells will boost capacity and expand coverage.




Most vendors in network infrastructure equipment and device chipsets support both TDD and FDD in their commercial products, indicating that they see a strong market potential for both flavors. This simplifies implementation and minimizes the additional OPEX/CAPEX costs to deploy LTE TDD. TDD is comparable to FDD in data throughput as well as latency measures, and handover (HO) procedures can be enabled from FDD to TDD and vice versa.



This is the new beginning of the hybrid LTE TDD/FDD deployment model.




The current state of TDD technology adoption


LTE TDD is expected to be widely adopted in 2015, reaching 89 million connections and representing roughly 25 percent of the total forecasted LTE connections for that year.





Figure 3. Ovum estimates that LTE FDD will take-off around 2012–13, while TDD will take off around 2013–14 for LTE TDD3.

[agchat]

I do not know if all has heard but we have a
grace of one more year on or wbb. Now i think
the point is to make clear to Sasktel and other
competitors is unlimited and reasonable pricing.
I am so dam sick and tired of these ads from
Sasktel for the city at $45 for 5mb unlimited a
month. It bad enough chemical, seed and
dealerships are hosing the shit out of us.

[sumdumguy]

Sasktel's saving grace is that Don McMorris is
the new minister. I am fairly confident that he will
get this mess straightened out.

[ColevilleH2S]

I can't wait to hear the conspiracy theory people
freak out because of Huawei's involvement ;-)

[mustardman]

Coleville what are you trying to say?
When China bugged the lawyers office that was doing the BHP takeover of Potash corp (true story) are you saying this was done with help from hauwei? LOL

[sumdumguy]

More Chinese involvement, yeh way, that is
exactly what we need. Pretty soon we will get
free noodles with our free High Definition.

[chuckChuck]

There is not any money to be made providing high speed to remote and rural customers because our numbers are low and cost are high.

But affordable high speed should now be considered a utility just like electricity was in the 1950s. We should be making this a political issue by demanding fair and affordable treatment from Sasktel and other providers.

The Sask. Government needs to make this happen. Market based solutions will be inadequate for rural and remote customers. The challenge is the technology is a moving target. But if the policy is reasonable cost and unlimited data for rural no matter what the technology, then that would be a much fairer policy.

Unlimited data on Iphones and other smart phones are probably the best unlimited option at this point. The phones can be tethered or used as a wireless hotspot. Speeds are good most of the time and they are portable. Just don't use them in the US for Data unless you have a plan.