New urgency on LTE Femtocells

Equipment vendors' focus on finalizing Long-Term Evolution (LTE)/Systems Architecture Evolution (SAE) standards specifications by the end of 2008 has raised concerns that femtocell standards work, which also faces a tight deadline, could suffer as a result.

Both LTE/SAE and femtocells -- or, Home Node Bs in 3rd Generation Partnership Project (3GPP) terminology -- have a deadline of around December this year for their specifications to be included in the next 3GPP release, Release 8. It's a critical target for both technologies.
Given the weight of influence behind LTE/SAE, not everyone is convinced that femtocells will meet that December cutoff. Despite the greater focus on so-called 4G technology LTE, other industry sources close to the standardization process believe the femto specs will be developed enough to be included in the initial Release 8 draft, even if they're not completed.

Any changes required after the "freeze" date, scheduled for December, would be done in a controlled way. But it's possible that not all of the functionality will be included as originally intended, and that some planned specifications work would need to be deferred to the next standards release, due one year later. Some femtocell executives aren't concerned that some details might miss this year's deadline, as the specs work in question isn't vital for initial home base station deployments.

But a lot is at stake for femtocells. Operators stress the need for standardized femto equipment, or at least a clear view of how vendors will support a standard in their equipment, before they can even consider large-scale deployments. A holdup in the standards would delay this new home base station market.

It's not hard to see how infrastructure suppliers would struggle to meet all the standardization demands for these two technology groups and how their resources could be stretched at the 3GPP. The next 3GPP release is chock full of other important technologies, in addition to femtos and LTE, such as those related to HSPA evolution and mobile IP core. On one hand there is LTE/SAE, an entirely new radio access technology, and mobile core, which has some of the world's biggest operators backing it as their so-called 4G next-generation infrastructures, with some carriers, such as Verizon Wireless , Vodafone Group plc, China Mobile Communications Corp. , and NTT DoCoMo Inc., already talking about commercial deployments. On the other hand, those same influential carriers are eager to put femtocell technology in their networks to see if the home base stations can live up to the promises of providing cost savings, capacity increases, churn reduction, and future new revenues, all without provisioning problems and economic subsidies.

The next plenary meeting of the Femto Forum Ltd. in September in Bangkok will be crucial for vendors to reach a consensus on some of the details in the Home Node B standard. Progress has already been made with the agreement on the Iu-h protocol for the link between the femto access point and femto gateway.

PicoChip has already announced earlier the availability of the industry’s first LTE femtocell and picocell reference designs, the PC8608 Home eNodeB and PC8618 eNodeB respectively. Now, Agilent announced that engineers from Agilent, picoChip and mimoOn have successfully tested a 3GPP LTE femtocell reference design using Agilent's MXA signal analyzer VSA test solutions.

The three companies have collaborated to ensure that the tests of their reference design meet the requirements of the LTE standard in development. Their engineering cooperation has advanced the technology needed to meet the demands of the emerging LTE femtocell market.

The test solutions used to validate the femtocell reference design included an Agilent MXA Signal Analyzer with the Agilent 89600 Series Vector Signal Analysis (VSA) software and its new 3GPP LTE modulation analysis option. This recently introduced option provides RF and baseband engineers working on early LTE devices with the industry's most comprehensive signal analysis solution for physical layer testing and troubleshooting. The Agilent 3GPP LTE VSA option enables LTE signal analysis from the analog or digital baseband through to the RF antenna for Node B infrastructure as well as end-user equipment prototype designs.

Currently, none of the parties involved in trialling Femtocells are interested in standardisations as they want to be the first in their pioneering approach. The standardisation activity may be a long way to go but their implementation may be longer way away.