Enhanced GPS Mobile Chipset

ASIA : NEC announced that it has developed a new signal processing device (µPD77534) and an RF/IF down converter IC (µPB1009) to enhance Global Positioning System (GPS) functions for cellular phones and other mobile applications.

The µPD77534 is an ARM7 TDMI-based System LSI for signal processing, fabricated on 0.15-micron process. As a chipset solution with µPD77534, NEC has also developed a new RF/IF down converter chip which is connected to the signal processor device and converts the high frequency GPS satellite signal to a low frequency signal used to establish location.

The new chipset, µPD77534 and µPB1009, enables correspondence in three modes: Mobile Station (MS)-assisted mode, MS-based mode, and autonomous mode. MS-assisted mode offers high sensitivity and fast positioning time, while it requires communication with the location servers which incurs transmission cost. On the other hand, autonomous mode does not require the transaction with the servers in obtaining assistant data but needs relatively longer time for positioning. MS-based mode has the characteristics that stay in the middle between the two. MS-assisted mode has already been introduced in the existing chipset (µPD77533 and µPB1007), and the two new modes are added this time allowing an optimal solution for the positioning in each occasion.

While enhancing the performance, the new chipset has achieved a remarkably low power consumption. The total power consumed in location mode is below 61mA, reduced by 40% from the existing chipset. In operating mode, the power consumption of µPD77534 and µPB1009 are 34mA and 27mA, respectively. The mounting area will also be reduced by 40% thanks to the smaller package size, which will greatly benefit the mobile handset makers who intend to implement GPS function in their products.

"These days, as mobile terminals such as cellular phone are starting to offer GPS services, calls for small and lightweight GPS handsets are increasing rapidly," said Tetsuro Kanai, general manager, 1st System LSI Division, NEC Electronics Corporation. "To meet such demands, we have to implement the functions that can minimize the amount of position detection calculation needed at the handset side, in addition to offer high-performance and compact devices. By introducing this chipset, we believe we can expand the potential of mobile applications deploying GPS function. New services such as position identification of emergency calls, providing town map and recreation information of the location to the phone callers, position identification of lost children and pets, and so on will be made available."

With its first product µPD77533, the signal processor of previous generation, NEC Electronics has been providing the solution to its customers that mitigates processing load at the mobile terminal for the past couple of years. The MS-based mode, incorporated in the device, decreases the amount of calculation at the handset by utilizing the data that the servers in the network called Serving Mobile Location Center (SMLC) download from GPS satellites and by having the servers operate the final calculation for positioning. However, while realizing highly accurate positioning even inside or between buildings, this method requires transmission cost in exchanging data between the terminal and the server. To pursue inexpensive optimal positioning, therefore, the new two modes are added in the new device µPD77534. In the MS-based mode, mobile handset receives assistant data from the server but does the final position calculation itself. In the autonomous mode, all the calculations are done in the handset side and data from the server is not required. By flexibly shifting the mode from one to another according to the situation, cost-effective GPS function can be achieved in mobile applications.

Pricing, Packaging and Availability
The µPB1009 is packaged in 44-pin Quad Flat Non Lead (QFN) package and will be available for volume production in October this year, at the price of 350 yen when ordered in quantities of 500,000 pieces or more. The µPD77534 is packaged in 161-pin Tape Fine Pitch BGA (TFPBGA) and will be priced at 1,000 yen for orders of 500,000 pieces or more. Its mass production is planned to start in April 2004.