Chandra Sekhar Bontu

DRX mechanism for power saving in LTE

Enhanced discontinuous reception mode is supported in long term evolution of 3GPP standards to conserve the mobile terminals battery power. Furthermore, there are additional advantages in using DRX, such as over-the-air resource saving on both the uplink and downlink to increase overall system capacity. One of the enhancements over 3G wireless systems is that in LTE DRX mode can be enabled even when the user equipment is registered with the evolved node-B. However, there is a need to optimize the DRX parameters, so as to maximize power saving without incurring network re-entry and packet delay. In particular, care should be exercised for real-time services. In this article the power saving methods in both network attached and network idle modes as outlined in LTE are explained. The optimum criteria to select the DRX mode are defined for different applications. Analytical/simulation results are presented to show the power saving/connection reestablishment and packet delay.

Built-in functional tests for fast validation of a 40Gbps coherent optical receiver SoC ASIC

An SoC ASIC is an integration of many complex components such as analog cores, digital cores, user defined logic, memories, etc. If not properly planed, lab validation of such an ASIC can be time consuming. This paper proposes a design for validation architecture that includes a built-in functional test for fast lab validation and system integration. The proposed scheme has been adopted in a 40 Gbps coherent optical transmission ASIC, which consists of 20 M gates and four 20 Gsps ADCs.