Original 45nm Intel® Core™ Microarchitecture

The Technical Challenges of Transitioning Intel® PRO/Wireless Solutions to a Half-Mini Card

INTRODUCTION

In this paper we give a brief overview of the technical challenges involved in transitioning the Intel® PRO/Wireless Wi-Fi solutions from a Full-Mini Card to a Half-Mini Card form factor. (We use the terms “Full-Mini Card” and “Mini Card” interchangeably.)

Over the past generations of Intel PRO/Wireless solutions, the team has been asked to continually increase functionality while decreasing board size. (Figure 1) shows the evolution of form factors starting with the original Mini Peripheral Component Interconnect (PCI) form factor of choice at the launch of the first Intel Centrino® Mobile Technology (CMT) platforms back in 2004–2005. The Intel PRO/Wireless 2100 2200 2915 series were all implemented using this Mini PCI Card form factor. In 2006, a new smaller form factor and Host Interface were introduced into the platform—the Mini Card—with a high-speed PCI Express interface. The intent of this smaller form factor was to enable the incorporation of two Mini Cards in the available space of the older Mini PCI Card, thus enabling more functionality in the platform. The Intel PRO/Wireless 3945abg was Intel's first IEEE 802.11abg Wi-Fi solution using this new form factor, which was part of the Napa family of CMT platforms. As the IEEE 802.11 Wi-Fi standard evolved, a new higher throughput technology was introduced called IEEE 802.11n that enables a Multiple In Multiple Out (MIMO) communication scheme. One of the key features of this new scheme is higher data throughput. The Intel PRO/Wireless 4965 was Intel's first IEEE 802.11n Draft MIMO solution to the market. It has two transmitters and three receive chains for data rates up to 300Mbps, using the same Mini Card form factor: in previous-generation technologies, there was only a single transmitter and a single receive chain. This amounts to a functionality compaction factor of 2.5:1 and a data throughput improvement factor of 5:1. This new wireless solution was introduced into the market at the end of 2006 and continues to be provided on the Santa Rosa CMT platforms.

Figure 1: Intel® PROWireless evolution

However, the ‘ever hungry’ market demands more functionality in less space. This market demand drove the development of a new form factor called the Half-Mini Card. Again, the intent is to enable platform integrators to put more wireless content into the platform by placing two Half-Mini Cards in the space where they once put a single Full-Mini Card just one generation ago. With respect to performance, the intent is to also improve the throughput by a factor of 1.5:1 thereby reaching data throughputs of up to 450Mbps.

In this paper, we describe some of the technical challenges and solutions the team faced while implementing this newer, smaller Half-Mini Card form factor while also increasing the functionality of the Wi-Fi system to a full three-transmitter and three-receiver 802.11n MIMO functionality. We discuss these issues in this paper:

• Half-Mini Card form factor standardization in the PCI-Special Interest Group (PCI-SIG)
• The Intel PRO/Wireless 5000 series of network adaptors
• Component and functionality partitioning
• Mechanical and physical requirements
• Printed Circuit Board (PCB) requirements
• Radio Frequency (RF) component sizes and challenges to meet regulatory emission certification requirements
• Thermal considerations and challenges

The team successfully met these challenges with the introduction of this latest family of Intel PRO/Wireless solutions 5300 and 5100 that are an integral part of the Montevina CMT platforms, by using the new Half-Mini Card form factor. These network adaptors will also be offered to customers in the older Full-Mini Card for the benefit of Original Equipment Manufacturers (OEMs) who continue to support the older, larger, single-sided form factor. This fact will also serve as a basis for comparison to better explain the challenges of converting the same product to the new, smaller Half-Mini Card form factor.

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