Daniel Iancu

A software-defined communications baseband design

Software-defined radios offer a programmable and dynamically reconfigurable method of reusing hardware to implement the physical layer processing of multiple communications systems. An SDR can dynamically change protocols and update communications systems over the air as a service provider allows. In this article we discuss a baseband solution for an SDR system and describe a 2 Mb/s WCDMA design with GSM/GPRS and 802.11b capability that executes all physical layer processing completely in software. We describe the WCDMA communications protocols with a focus on latency reduction and unique implementation techniques. We also describe the underlying technology that enables software execution. Our solution is programmed in C and executed on a multithreaded processor in real time.

The sandbridge SB3011 platform

This paper describes the Sandbridge Sandblaster real-time software-defined radio platform. Specifically, we describe the SB3011 system-on-a-chip multiprocessor. We describe the software development system that enables real-time execution of communications and multimedia applications. We provide results for a number of interesting communications and multimedia systems including UMTS, DVB-H, WiMAX, WiFi, and NTSC video decoding. Each processor core achieves 600 MHz at 0.9 V operation while typically dissipating 75 mW in 90 nm technology. The entire chip typically dissipates less than 500 mW at 0.9 V.

The sandbridge SB3011 SDR platform

This paper describes the Sandbridge Sandblaster real-time software defined radio platform. Specifically we describe the SB301I system on a chip multiprocessor. We describe the software development system that enables real-time execution of communications and multimedia applications. We provide results for a number of interesting communications and multimedia systems including UMTS, DVB-H, WiMAX, WiFi, and NTSC video decoding. All results presented are from completely implemented systems from RF through baseband

Instruction set extensions for software defined radio on a multithreaded processor

Software defined radios, which provide a programmable solution for implementing the physical layer processing of multiple communication standards, are widely recognized as one of the most important new technologies for wireless communication systems. Emerging communication standards, however, require tremendous processing capabilities to perform high-bandwidth physical-layer processing in real time. In this paper, we present instruction set extensions for several important communication algorithms including convolutional encoding, Viterbi decoding, turbo decoding, and Reed-Solomon encoding and decoding. The performance benefits of these extensions are evaluated using a supercomputer class vectorizing compiler and the Sandblaster low-power multithreaded processor for software defined radio. The proposed instruction set extensions provide significant performance improvements, while maintaining a high degree of programmability.

Instruction set extensions for Reed-Solomon encoding and decoding

Reed-Solomon codes are an important class of error correcting codes used in many applications related to communications and digital storage. The fundamental operations in Reed-Solomon encoding and decoding involve Galois field arithmetic which is not directly supported in general purpose processors. On the other hand, pure hardware implementations of Reed-Solomon coders are not programmable. In this paper, we present a novel algorithm to perform Reed-Solomon encoding. We also propose four new instructions for Galois field arithmetic. We show that by using the instructions, we can speedup Reed-Solomon decoding by a factor of 12 compared to a pure software approach, while still maintaining programmability.

Software implementation of WiMAX on the sandbridge sandblaster platform

This paper describes a Sandbridge Sandblaster system implementation including both hardware and software elements for a WiMAX 802.16e system. The system is implemented on the fully functional multithreaded Sandblaster multiprocessor SB3010 SoC chip. The entire communication protocol, physical layer and MAC, has been implemented in software using pure ANSI C programming language and it executes in real time. In this paper, we also present a radio propagation analysis specific to the Samos island at the workshop location, and the DSP execution performance.

Software Solutions for Converting a MIMO-OFDM Channel into Multiple SISO-OFDM Channels

We present a software approach for MIMO-OFDM wireless communication technology. We first show that complex matrix operations like singular-value decomposition (SVD), diagonalization, triangularization, etc., can be executed efficiently in software using a combination of CORDIC and unitary rotation algorithms in a multithreaded SIMD processor. We then investigate and analyze the transformation of a MIMO-OFDM channel into multiple independent SISO-OFDM channels by means of the SVD. The algorithms are implemented on the Sandblaster processor. The numerical results indicate that the CORDIC-augmented processor provides a significant reduction in the computing time of more than 47% over the standard sandblaster processor when converting a 4-by-4 MIMO-OFDM channel into four SISO-OFDM channels. The technique is applicable to emerging wireless communication protocols, such as WiMAX and Wi-Fi, and provides the flexibility required to adapt to continually changing and evolving standards without the need for expensive hardware redesigns and respins.

Instruction set extensions for software defined radio

Software defined radios provide programmable solutions for implementing the physical layer processing of multiple communication standards. Mobile devices implementing these standards require high-performance processors to perform high-bandwidth physical layer processing in real time. In this paper, we present instruction set extensions for several important communication algorithms including cyclic redundancy checking, convolutional encoding, Viterbi decoding, turbo decoding, and Reed-Solomon encoding and decoding. We also present hardware designs for implementing these extensions, along with estimates of their area, critical path delay, and power consumption. The performance benefits of these extensions are evaluated using a supercomputer-class vectorizing compiler and the Sandblaster low-power multithreaded processor for software defined radio. The proposed instruction set extensions provide significant performance improvements at relatively low cost, while maintaining a high degree of programmability.

Analog Television, WiMAX and DVB-H on the Same SoC Platform

This paper presents a SW reconfigurable platform, capable of executing in real time both analog and digital television protocols as NTSC, PAL, SECAM and DVB-H. Our platform is also capable of executing WiMAX at 2.9 Mbps in real time, as well as other mobile telephony protocols like 3G UMTS or CDMA200. SW reconfigurability and low power consumption makes our platform suitable for mobile applications. Current analog and digital television systems have been developed in a combination of analog and/or digital hardware due to high computational processing requirements. They are also mostly limited to a single function either analog TV or, digital TV. DSPs in these systems have been limited to speech coding and orchestrating the custom hardware blocks. Despite the fact that in high-performance systems there may be over 2 million logic gates required to implement physical layer processing, the implementation may take many months to finalize. After the logic design is complete, any errors in the design may cause up to a 9 month delay in correcting and refabricating the device. This labor intensive process is counter productive to fast development cycles. In our approach, the entire physical layer is executed in SW using the SB3011 DSP from Sandbridge Technologies (Glossner et al., 2003) allowing fast development cycles and support of multiple functions

On the performance of 3GPP LTE baseband using SB3500

In this paper, we present the system and computational performance of 3GPP LTE baseband processing implemented on the Sandbridge SB3500 processor. Maximum Ratio Combiner (MRC) and Linear Minimum Mean Square (LMMSE) are adopted to be the baseline receiver algorithm for various downlink transmission modes. The system performance evaluation, through end-to-end system simulations, shows that the conformance test requirements published by the 3GPP group are met with a design margin ranging from 0.8 to 2 dB. The computational complexity of our LTE category 2 implementation is such that the entire baseband processing executes in one SB3500 processor.