One of TI’s small cell basestation SoCs,TCI6614, for example, features quad C66x DSP cores and ARM Cortex-A8 and offers simultaneous dual mode, meaning that it can run two standards at the same time – LTE and WCDMA. That chip can support 128 users, according to TI.
Compared to that, Freescale’s PSC9132 supports only 64 users. Asked about that difference, Freescale’s Aylor noted: “We can absolutely support 128 users in our picocell SoC. But it all depends on the specific traffic patterns and the use case.” He added, “We are quoting more realistic numbers based on a typical use case scenario.”
It turns out that a YouTube download, the sort of activity often blamed for congestion on the wireless network, doesn’t necessarily restrict the number of users a small-cell basestation can support. Aylor explained, “Bigger packet applications like YouTube video are actually easy to deal with. Sure, big packets require a lot of data, but it is a simpler operation. It’s not signaling intensive.”
In contrast, GPS/Google Map search on a smart phone does not require a lot of data, but it creates heavy signaling stress on a basestation, said Freescale’s Aylor. “Functions like ‘scheduling’ can be better handled by a processor core in our SoC, rather than a DSP,” he added.
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Freescale has made the most of its knowledge of the wireless market and extensive IP portfolio to develop the new SoCs. The QorIQ Qonverge processors are built on market-tested Power Architecture cores, programmable StarCore DSP technology and baseband hardware acceleration engines already deployed in multiple LTE macrocell basestations around the world.
Leveraging StarCore SC3850 DSP and Power Architecture e500 MPU cores, “the new QorIQ Qonverge SoCs are distinguished by offloading Layer 2 processing and above to MPU cores instead of DSP cores, delivering significant efficiency advantages,” according to Freescale.