- Published on Wednesday, 11 May 2011 19:10
LTE (Long Term Evolution) is still a relatively new technology, even though the first standard (3GPP Release 8) was published in 2008 and tens of commercial networks have been launched worldwide. Femtocells have been designed into the LTE specification from the start, and a growing R&D community has evolved over the last couple of years.
What is perhaps surprising, is that many of the LTE chipset vendors and femtocell manufacturers are different from those already established in the 3G femtocell world. There are a number of new entrants for both silicon chips and software stacks.
The way in which LTE femtocells are likely to be rolled out also has an impact. Rather than being launched initially as very low cost residential devices, many network operators are looking to use them for mass deployment in public areas. This means higher unit prices and lower volumes.
By using larger numbers of smaller cells, the network will offer higher data rates (because of shorter distances to the cells), much higher overall capacity (because the frequency spectrum is reused more) and longer battery life (because of lower power transmission from consumer devices).
Likely to be more powerful than some of the residential 3G femtocells, these LTE femtocells will be able to handle peak throughput data rates of tens of megabits shared between concurrent users. They’ll require Ethernet (or at least very fast DSL) wireline connections but relatively little power or physical space.
LTE femtocell chipset vendors
Many of the chipset vendors already present in the larger macrocell basestation designs have offered or demonstrated LTE femtocell designs. The higher pricepoint of an LTE femtocell – there aren’t yet demands for a $50 residential version – allows larger/higher capacity designs to be adapted for this purpose.
The list below (in aphabetical order) has been drawn up from a variety of press releases and announcements in recent months, and is not exhaustive. Please comment below to note any omissions or discrepancies.
Picochip: Demonstrated a working LTE reference design at MWC in Feb 2011, with its own chipset running the L1 physical layer complemented by Continous Computing protocol software running on a Cavium processor. The solution was shown interworking with a commercial LTE USB dongle. Picochip have since been acquired by Mindspeed.
DesignArt: Offer a SoC (System on a chip) for use in LTE macrocells and femtocells. Partner with Continuous Computing for the L2/L3 protocol stack. DesignArt have since been acquired by Qualcomm and their technology incorporated into the latter's products.
Freescale: Offer their StarCore DSP for Layer 1 of LTE femtocells, both FDD and TDD modes.
Mindspeed: Demonstrated an LTE femtocell at MWC in Feb 2011, jointly with Airwalk (femtocell vendor) and Lime Microsystems (RF front end chipset). Continuous Computing protocol stack also supports this combination.
Qualcomm: views the logical long term solution to be heterogeneous networks (or HetNets) as it calls them, which would include picocells and femtocells. LTE femtocells are said to be on their roadmap.
Texas Instruments: Announced partnership with Continous Computing and mimoOn for LTE femtocells, based on their femtocell-optimized TCI6485 and TCI6489 chips. They also jointly announced with Ubiquisys a joint project to develop dual mode HSPA/LTE femtocells for public space and metro environments. These will take advantage of TI’s higher capacity chipsets and Ubiquisys’ proven SON (self-optimising/organizing network) software.
Xilinx: Similar to Altera, they are an FPGA vendor able to position their standard products as suitable for LTE femtocell designs.
Other well known manufacturers may also enter the LTE femtocell marketplace at a later date.
LTE femtocell software vendors
There are separate vendors specialising in the LTE Layer 1 (PHY or physical layer) and the Layer 2/3 Protocol Stacks. Some offer both. This complementary software often runs on a different processor.
Aricent: Although very much more of a services company than a software product business, they showcased LTE software as early as 2009. Their solution brief outlines a wider range of services for femtocells which also include LTE. Public Wireless selected their software for their LTE small cell in 2012.
Continuous Computing (later acquired by Radisys): Claim over 20 LTE design wins to date (although not all are femtocell size). Demonstrated both FDD and TDD LTE femtocells at MWC 2011.
mimoOn: Complete LTE stack adaptable for SDR, DSP and ASIC chipsets. Demonstrated Layer 1 at MWC, running on the Freescale chipset. Their software separately packaged up as Mi!SmallCellPHY for PHY Layer 1 one and Layer2/3 small cell stack.
Nomor: Smaller German company focussed entirely on LTE software, having been involved in standards and development for some years. Also offers test software. Demonstrated LTE basestation on Mindspeed hardware platform at MWC 2011.
This list is far from exhaustive. It doesn’t list the femtocell vendors themselves – only the hardware and software component suppliers. If you are aware of any omissions or errors, please comment below or email me to correct it.
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