C-RAN : SDR on steroids
I recently had a Cloud-RAN (C-RAN) discussion with Gilad Garon, CEO of ASOCS, a privately held company that develops and markets multi-core processors (Their own design) that enable software to program physical layer functions and algorithms.
Although ASOCS has been around for ten years, their new business direction is two-pronged:
- Silicon licensing IP business (ARM model)
- Re-focus from baseband in smart phones and tablets to wireless infrastructure.
They have full stacks for 802.11 and other wireless standards, but they are not just a processing company. They are virtualizing the wireless physical layer.
With OFDM for 4G, a dense network with more base stations—users are at 100 Mbps! Where 3G needed 10 macro base stations, 4G needs about 250 base stations for the proper coverage at these rates.
Mobile networks have greatly evolved since the days of GSM, the beginning of digital radio technology, and the move away from the analog base station technology called Advanced Mobile Phone System (AMPS) in Ma Bell’s time. See Figure 1.
Figure 1: The mobile network evolution (Image courtesy of ASOCS)
I have personally witnessed this evolution since I was with Burr-Brown and TI for 23 years and my account, as corporate account manager/apps engineer, was AT&T, Lucent Technologies and ultimately Alcatel-Lucent worldwide. I also covered Nortel Networks years ago, so when I tell you this C-RAN disruption is truly a game-changer---believe me it is!
Garon’s company sees wireless communication in this way: Big Data and communication signal processing are converging into a single IP core network within massively sized, power-hungry Data Centers.
Mobile customers ultimately will roam seamlessly in any type of cellular and multiple wireless standards, as well as in White Space (the unused radio spectrum between TV stations) and person-to-person mesh networks.
Next, machines will connect to networks and each other in many different communication technologies. These will all need modem intelligence and produce tens of billions of devices.
ASOCS sees the cellular infrastructure heading towards a disruption point in which current telecom equipment carrier’s eco systems will not be sustainable.
ASOCS’ plan is to enable the move of value from the incumbent SoC suppliers such as Freescale and TI, to the processing companies such as Intel, ARM and CISCO.
Conventional base stations are called Radio Access Networks (RAN), but Cloud-RAN will move conventional digital base station electronics away from the cell tower, 20 to 50 km away, back in the data center.
They will no longer use conventional ASICs for the macrocell, but instead, off-the-shelf X86, ARM or AMD processors in the future and with ASOCS’ technology added, they will enable the data centers to look like software.
Editor’s note: OK analog engineers, bear with me, because I need to give our digital hardware and software brethren’s side an introduction in order to set the stage for Part two of this article---the analysis of the power management and clocking schemes behind C-RAN as well as the I & Q streams and Coordinated Multipoint (CoMP) antenna transmission functions from the remote antennas. Here goes:
Network Function Virtualization (NFV) for all network functions from packet to signal processing is the solution according to ASOCS. Cloud RAN (C-RAN) will be a key node in this NFV. See Figure 2.
Figure 2: C-RAN is a key node in the NFV and a move from proprietary “closed doors “ DSP’s/ASICS to open platform GPP (Image courtesy of an Intel white paper)