Altera provides enabling solutions, allowing OEMs to maximize their R&D investment by focusing on differentiating their products. These solutions are targeted for Stratix® IV FPGAs and HardCopy® III and HardCopy IV ASICs, and can be easily integrated using versatile tools such as SOPC Builder for an application-specific system on a chip (SoC). The ease of migration from a Stratix IV FPGA to a Hardcopy III or HardCopy IV ASIC further offers OEMs the lowest total cost of ownership.
System Architecture
A typical macro or micro base transceiver station (BTS) channel card consists of a combination of ASICs or FPGAs, digital signal processing (DSP) SoCs, and communication processors communicating with each other via a Serial RapidIO® (SRIO) switch (see Figure 1).
Figure 1. Typical Macro or Micro Channel Card
With the advent of Altera’s 40-nm products, Altera can now offer an SoC framework to build a custom long term evolution (LTE) SoC. From a system architecture perspective, Altera has adopted a very simple paradigm—single device per sector. Multiple sector scalability is achieved by device replication. This scaling is further augmented by the pin-compatible vertical migration capability of Altera® devices; so if an OEM wants to target for example a 10-MHz LTE configuration instead of a 20-MHz LTE configuration, they have the option to scale down within the family to a smaller (pin-compatible) device. The architecture within the device however would remain the same. These multiple levels of scalability and flexibility are also applicable to HardCopy series ASICs. You can achieve scalability by migration by extending the concept of design re-use across Altera device families (see Figure 2).
Figure 2. Scalability by Migration
System-on-a-Chip (SoC) Framework
Adopting an SoC approach by combining intellectual property (IP) blocks with a novel C-based control technique creates a more productive design and integration methodology and ensures that design flow is familiar.
- IP blocks act as hardware function calls, making them as easy to use as software functions.
- Built-in DSP blocks are used to implement appropriate datapath operations, easing productivity for algorithmically complex functions.
- Control is written in C code running on a specialized processor.
- The SoC architecture is built by assembling library components within SOPC Builder, which synthesizes the connectivity.
In the case of the LTE macrocell, the methodology allows an efficient and flexible solution, with design entry that is familiar to and suitable for hardware and software engineers. Available processing power on Altera’s FPGA allows the required system to be instantiated on a single FPGA. Moreover, the design methodology allows a transition to a HardCopy ASIC, while still retaining software programmability.
Altera provides an SoC framework that enables complex control flows that are implemented using software-controlled hardware. A receiver consists of a set of DSP engines that make good use of the silicon resources. You can scale the number of these engines for the target configuration. These engines are then coordinated using software running on an SoC controller processor.
The advantages of this approach include:
- Reduced design time since much detail is abstracted into software, eliminating the need for repeated FPGA place-and-route design cycles and timing closure cycles.
- Software updates facilitate design modifications and field upgrades with minimal risk.
The benefits of Altera’s SoC Framework are:
- Custom baseband on a chip significantly lowers BOM cost and achieves board-level efficiency
- Highly integrated 40-nm chip lowers size, weight and power (SWaP)
- Highly scalable and flexible SoC platform architecture allows you to scale up or down for various targets
- BTS Type: macro, micro, pico, femto (MIMO channels, BW, sectors)
- Functionality: PHY only, PHY+MAC, PHY+MAC+digital IF
- Software capability with reprogrammability retained in FPGA and ASIC fabric
- Productivity enhancing debug tools
To learn more about how Altera can help with your custom SoC, please contact your local Altera sales representative.
