Small cell chipset industry converging into three distinct market approaches

Chipset providers are concentrating their small cell products into indoor, macro equivalents and Cloud RAN approaches, argues David Chambers of ThinkSmallCell

Small cell chipset industry converging into three distinct market approaches

The large investments made by silicon vendors are worth watching as a long-term indicator of industry direction. These companies effectively place multi-hundred million dollar bets on how the wireless industry will transform itself in a 3-5 year time window, and stand to win or lose huge returns.

The smartphone industry has seen Qualcomm capture a majority market share recently, seeing off Broadcom which has withdrawn to fight other battles.

The small cell industry has also seen consolidation through acquisition, with around half a dozen companies left setting out their stall in the market. Broadcom acquired Percello, Intel bought Mindspeed (and thus Picochip), Qualcomm captured DesignArts – these and others continue to invest heavily as the market evolves.

The scope of small cells has expanded from the original residential femtocell through to higher capacity urban outdoor metrocells. Some vendors even include up to 20W models in their ‘small cell’ range. The Small Cell Forum uses classifications of residential, enterprise, urban and rural which help segment the market.

In-building small cells
In the residential sector, cost is the priority. With some 10 million units shipped to date, there is volume to offset early investments, but price pressure is intense. The entire BOM (bill of materials) should be well under $100, leading to innovative cost cutting measures and high levels of integration.

Picochip dominated the early residential femtocell designs including AT&T’s popular 3G Microcell, but Percello (since acquired by Broadcom) quickly matched its capability and won over the major players.

These residential designs evolved from the original four concurrent call capacity to handle eight and then 16 or more, making them suitable for busier enterprise applications.

Broadcom then introduced LTE support, allowing the same chipset to be remotely configured for 3G or LTE. We also saw larger scale enterprise RAN systems such as SpiderCloud adopt its chipset, using a local controller to manage up to 100 radio nodes for the largest indoor buildings.

Picochip was acquired by Mindspeed in early 2012, and lost market share. In late 2013, Intel acquired Mindspeed’s wireless assets, investing and stabilising that part of the business to ensure continuity of supply and support. Recently, Contela has brought out a new LTE product based on its Transcede processor.

Meanwhile, Qualcomm has been investing and developing in this market for some years, recently winning several key accounts. Well known brands including ip.access, Alcatel-Lucent, Airspan and Airvana have all demonstrated or are shipping commercial products using its chipset.

Unlike others, Qualcomm provides a tightly integrated solution with its own RF front end, GPS receiver and timing. It’s made a major play of its Ultra-SON features that improve the performance of groups of closely located small cells. In June, it announced a smaller version of its existing FSM99xx chipset family, aimed at lower capacity/lower cost products.

Although there are some outdoor metrocell products, it’s fair to say that these three vendors are more focussed on indoor buildings than outdoor. They’ll be competing with DAS (Distributed Antenna Systems) for some of the larger venues.

Macro equivalency and compatibility
Texas Instruments (TI) and Freescale are both major players in the traditional macrocell business. TI invested heavily in its Keystone architecture, which delivers macro-equivalency throughout a range that spans enterprise to public access. Its approach is to allow OEMs to reuse the same software across its entire product portfolio from macrocell to microcell to picocell.

An example is NSN’s Flexizone, where its LTE picocell is believed to be based on the same chipset family as its macrocell products. It’s highly likely that ZTE’s public selection of Freescale’s BSC9132 chip was for the same reason.

The approach can reduce product development time, but involves more than simply porting software from one platform to another. Traffic profiles and signalling levels differ in dense urban environments.

OEM vendors also tout the benefits of years of field experience, which ensure compatibility with the widest variety of deployed handsets. There is less emphasis on product cost per se, more on lifetime total cost of ownership. That involves ensuring adequate processor performance to handle future software upgrades, highly automated configuration and SON features, which may not be present in macrocells.

Neither of these companies is targeting the low cost residential market, where consumer electronics price points and volumes apply. They promote the desire for macro equivalency, highlighting accelerators and optimisations designed from experience gained from their existing macrocell field experience.

Centralised approach using Cloud RAN
A third approach relates to Cloud RAN, where the intensive RF baseband processing is shifted from the edge of the network to be co-located at central datacentres. This would typically need dark fibre from each antenna, shifting the economics from one of equipment cost to that of backhaul.  

Other benefits of this centralised approach are that multiple radio heads can be tightly synchronised, using some of the most advanced LTE-A features to squeeze the highest performance from available spectrum.

This may require the backhaul not just to be high capacity dark fibre, but finely tuned for phase timing synchronisation. In practical terms, this may involve physically extending or shortening the fibre cables by many metres to align the delay.

Co-located processing scales best when using the highest performance building blocks, and this is where Cavium and Intel would bring their expertise. While there’s nothing to stop other baseband vendors playing in this space, it’s these two that seem to be making the strongest marketing in this space.

Cavium recently announced a monster ThunderX SC chip with up to 48 ARM cores. They are present in many large scale datacentre and network processing systems, looking to get into the RF processing side of things. It also announced standalone LTE small cell designs, such as that for Korean network LG U+.

Categorisations such as this are never hard and fast. None of the above precludes any individual vendor from playing in more than one segment. Indeed, several already do. But it does help position the needs and focus for different parts of the market.

Can these three distinct market segments continue to thrive? In terms of volume, the in-building sector is most promising in the short term and probably where we’ll see the most upset. Urban densification, especially for LTE, will be a natural market for the mainstream RAN vendors to evolve into.

Protecting their investments and minimising risk naturally encourages them to stick with tried and tested platforms. Cloud RAN is a new approach that may suit specific markets and applications where dark fibre is easily and cheaply available.

David Chambers is a recognised authority on small cells and publishes and manages the ThinkSmallcell website:


Selected publicly announced chipset selections

  • Airspan: Picochip, now Qualcomm
  • Alcatel-Lucent: Picochip, Broadcom now Qualcomm
  • Airvana: Qualcomm for SoHo product, OneCell not named
  • Contela: Picochip, now Intel
  • Cisco (formerly Ubiquisys): Broadcom and TI
  • Huawei: Not publicly named, but believed to be one of the major brands
  • LG U+ (Korea): Cavium
  • Spidercloud: Broadcom
  • ip.access: Picochip, now Qualcomm
  • Purewave: TI
  • Qucell: Shipping Broadcom, recently demonstrating Qualcomm
  • NSN: Same as its macrocell products
  • ZTE: Freescale

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