LTE-Advanced Advances in New Broadcom Modem

Broadcom has begun sampling what it claims is the industry's smallest LTE-Advanced modem, one designed to link the next generation of smartphones and tablets to the next generation of cellular networks starting in early 2014.

LTE

Broadcom has begun sampling what it claims is the industry's smallest LTE-Advanced modem, one designed to link the next generation of smartphones and tablets to the next generation of cellular networks starting in early 2014.

The BCM21892 modem is based on a 28-nanometer silicon process, the current target for chipmakers and device manufacturers to keep device innards compact and to reduce power consumption.

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Broadcom says the modem's board area is "approximately" 35% smaller "than current industry solutions," almost certainly an oblique reference to rival Qualcomm which is an LTE market leader. This is Broadcom's first LTE modem product.

The modem's baseband supports all current 3GPP standards: both the FDD and TDD flavors of LTE, HSPA+ at 42Mbps, the TD-SCDMA networks found mainly in China, and EDGE/GSM.

But it also supports LTE-Advanced (formally LTE Release 10), which features a number of capacity-boosting changes, including being able to aggregate separate signals (or "carriers"), and higher spectral efficiency. LTE-Advanced offers a peak downlink data rate of 3Gbps, and a peak uplink data rate of 1.5Gbps. By comparison, for current LTE networks the highest theoretical data rate is 300Mbps in the downlink and 170Mbps in the uplink, according to 3GPP.

T-Mobile announced last year that it will start deploying the first LTE-Advanced network in the U.S. starting this year.

The new modem has an integrated "world-band radio" that supports the very wide range of LTE frequency bands being used around the world. That will be vital as LTE carriers gradually move to allow LTE roaming as they do today for 3G connections.

Broadcom is also offering Voice over LTE (VoLTE) support in the modem. Currently, LTE is a data-only network: Voice calls are actually handed off to a 3G WCDMA connection, a "solution" that requires an extra chip. Broadcom says its VoLTE service uses 40% less power than the WCDMA voice call.

The race to reduce LTE chip sizes and integrate other components with them, both to optimize the space in smartphones and to make them more power efficient, reveals the complex trade-offs faced by phone makers such as Apple. Apple was criticized by many tech blogs, for example, for not bringing LTE to the iPhone earlier than September 2012. But feature advances have to be weighed against other self-chosen design constraints such as the phone's thinness, weight and battery life.

John Cox covers wireless networking and mobile computing for Network World.A Twitter: @johnwcoxnwwA Email: john_cox@nww.com

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This story, "LTE-Advanced Advances in New Broadcom Modem" was originally published by NetworkWorld .

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