Leadcore Technology Co. Ltd, a subsidiary of Datang Group, is a silicon success story from China. It recently made waves by snatching the baseband socket from Qualcomm in Xiaomi’s sub-$100 LTE smartphone Redmi 2A. Leadcore’s L1860C chipset included quad-core 1.5GHz CPU and Mali-T628MP2 GPU from ARM and LTE modem from CEVA Inc.
What happened next? Xiaomi snatched Leadcore as a silicon partner to go vertical like smartphone rivals Apple, Huawei and Samsung. Marshal Cheng, a senior executive at Leadcore, recently spoke to EE Times to share the details of how the fabless chipmaker will collaborate with Xiaomi in developing customized processors.
Cheng also talked about the fabless firm’s early struggles while dealing with IP products like ARM and ZSP cores. According to Cheng, Leadcore’s real breakthrough came in 2012, when it teamed up with CEVA and licensed its software-defined radio (SDR)-based modem solution. That laid the foundation of Leadcore’s ambitious roadmap for LTE chips and also won Xiaomi’s attention.
It’s worthwhile to note that modems, especially multimode LTE modems are hard to design. A baseband processor digitizes and compresses the voice signal, modulates it onto a wireless signal, and carries it through the wireless infrastructure and vice versa. It’s highly challenging for chip designers to create a powerful communication processor that meets stringent power constraints.
Software modem replaces dedicated baseband system
The CEVA-XC, a fully programmable solution, supports multiple air interfaces in software, including LTE, HSPA+, 3G, and 2G. The flexibility of a software modem allows system-on-chip (SoC) designers to handle previously separate functions on a single DSP and gain a significant reduction in cost and power. In other words, instead of building separate chips for each wireless standard, baseband designers can build a single chip that can adapt to each market with a simple change of software.
Will Strauss, President & Principal Analyst at Forward Concepts, acknowledges CEVA’s role in redefining the DSP architecture. “CEVA introduced special-purpose DSPs such as the CEVA-XC that enable software-based modems and a unified platform for Wi-Fi, 3G, LTE and LTE-A with power and die size on a par with fixed-function modem designs.” CEVA’s configurable processor cores can also scale across a wide range of performance levels and enable the high reusability and fast time-to-market.
Leadcore, like most of the SoC houses in China, uses microprocessor cores from ARM. Strauss notes that another crucial factor in CEVA’s success is its close collaboration with ARM. CEVA ensures comprehensive support for the latest industry-standard interconnect and coherency protocols, enabling their mutual customers to leverage the inherent advantages of designing ARM plus CEVA-XC multicore SoCs.
Spreadtrum: China’s Baseband Pioneer
In retrospect, Leadcore’s decision to use CEVA’s soft modems was spot-on. The modems for LTE-based 4G wireless devices require almost twenty-fold increase in processing horsepower compared to 3G modems. So replacing dedicated baseband systems with the software approach came as a welcome relief to mobile SoC makers like Leadcore.
The second tale of CEVA’s association is about another ARM licensee in China: Spreadtrum Communications. However, unlike Leadecore, the relationship of CEVA and Spreadtrum goes back to the early 2000s, when mobile phone makers mostly employed specialized baseband ASICs. Spreadtrum, soon after its inception in 2001, joined hands with CEVA and the outcome of their partnership was SC6600, the first baseband chip for GSM/GPRS handsets developed in China.
Then, in November 2004, Spreadtrum announced that it has successfully developed the multi-band chipset SC8800, the first complete mobile SoC supporting GSM, GRPS and TD-SCDMA standards. Spreadtrum was the first company in China to develop baseband solutions for the country’s homegrown TD-SCDMA 3G standard. Time Division Synchronous Code Division Multiple Access or TD-SCDMA is air interface for China’s 3G wireless standard. The world’s first baseband chipset for the China 3G standard—powered by CEVA’s low-power Teak DSP core—was developed in less than one and half years.
Spreadtrum’s Mocor platform is customizable turnkey solution for handset OEMs
Later, in 2006, Spreadtrum expanded its design partnership with CEVA when it licensed the CEVA-X1620 DSP and CEVA-XS1200 sub-system for its upcoming 3G wireless baseband processors. Spreadtrum made a strong bet on TD-SCDMA standard at a time when industry watchers were skeptical about its potential amid the intense two-way race between the European W-CDMA and Qualcomm-backed cdma2000 standards.
Spreadtrum’s gamble on this brand new 3G technology paid handsomely and now it leads China’s TD-SCDMA smartphone market with more than 50 percent of market share. In April, the second largest chipmaker in China made the long-awaited leap of faith toward LTE-based 4G wireless and announced volume shipments of its quad-core 5-mode LTE platform, SC9830A. Again, the SC9830A chipset is based on DSP cores licensed from CEVA.
It’s worthwhile to note that CEVA has been among the semiconductor outfits that focused on China early on. According to the quarterly results, CEVA completed 12 new license agreements during the first quarter of 2015, and six of the new licensees are based in Asia. In other words, nearly half of company’s DSP core and connectivity IP business comes from Asia.
Majeed Ahmad is author of books Age of Mobile Data: The Wireless Journey To All Data 4G Networks and Essential 4G Guide: Learn 4G Wireless In One Day.