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Top1. Introduction
Wireless communication requires continuous development of new standards to satisfy ever increasing user demands. This is true not only for cellular standards (e.g. GSM, WCDMA, HSDPA, 3GPP-LTE) but also for other wireless standards (e.g. WiMAX, WLAN, DVB-H, DVB-T2). There is a challenge to implement these standards power-efficiently with mandated latency and throughput constraints. Additionally, there are design costs (cost of used resources, silicon area) and time-to-market constraints. Especially, NRE (Non-Recurrent Engineering) costs associated with the design and tooling of such complex chips are growing rapidly. One universally adapted solution to tackle such challenging goals is platform-based design (Sangiovanni, 2001). A platform-based design typically uses a mix of programmable and full custom ASICs to achieve flexibility, extensibility in design and at the same time a good control over all design costs. Additionally, a systematic platform-based design flow is developed to start from application algorithms and end in a mapping on a silicon chip – either dedicated custom-ASIC or a programmable processor. This way, platform-based design can trade-off various components of manufacturing and design costs while sacrificing as little as possible on potential design performance. In our design approach for wireless mobile terminals, we have used platform-based design based on reprogrammable radio architectures (broadly referred as Software Defined Radio). In this paper, we discuss mainly two aspects: the architecture of the platform and the design flow used in taking the platform architecture to tape-out. Discussion about design flows for mapping applications on such platforms can be found in (Palkovic, 2010).
In terms of implementation of wireless standards, in this paper we mainly focus on the baseband part in the receive path of the physical layer (PHY). A typical implementation architecture for such a receive path contains a Digital Front-End (DFE), BaseBand Engine (BBE) and Outer MoDem (OMD). Most of the wireless platform architectures available today emphasize on the BBE which performs the computation-intensive inner modem processing. However, we believe that equal attentions should be given to two more aspects: interconnect between components and overall control flow. In this paper, we introduce a platform architecture that uses decentralized control and a novel interconnect between state-of-the-art components (ASICs and Domain Specific Instruction Processors, DSIPs) to minimize communication and control overhead. With our architecture we have made three key achievements. First, our platform can support multiple wireless standards (WLAN, 3GPP-LTE, DVB-T2) achieving mandated latency and throughput constraints. Second, with our architecture, we can run two concurrent and independent data streams. And third, we can switch among different wireless standards within an order of 100μs. This paper describes first the platform architecture and then design flow used to take this platform architecture towards a tape-out. The main contribution in our design flow is the attention given to early energy consumption estimation.