High-speed Wireless LAN Technology

Ricoh's wireless LAN technology enables high-speed communications in a secure manner with excellent connectivity.

Wireless LAN becomes popular in offices. In fact, the office where a network is operated only by wireless LAN has appeared. Demands are increasing for layout independent network where PCs, printers, and multi-function printers (MFPs) are connected without cables. An optional board featuring this technology adds speed and high security to document management including printing and “scan-to-Email” in a wireless environment. Another advantage of this technology is a stable connection that is not easily affected by fluctuations in the wireless environment, under the rapid increase in a wireless LAN node in recent years.

This technology is carefully implemented to ensure stable, high-speed wireless LAN communications. The antennas are specifically optimized for desktop and floor-standing printers/MFPs. We integrated features needed for this new technology into the control LSI (with built-in CPU and memory) with embedded software.

Figure 1: Option board for desktop devices and installation

Figure 2: Option board for floor-standing devices and installation

Ricoh developed the following core modules for the technologies conforming to IEEE802.11 wireless LAN standards:

Figure 3: Modules developed by Ricoh

(1) Control software corresponding to MAC sublayer

Ricoh developed the control software for the hardware modules in this sublayer and lower-level layers. The software receives commands from higher-level layers (such as device drivers) and establishes communications with the destination terminal using protocols conforming to the standards. The development team thoroughly verified interconnectivity with a variety of terminals, and carefully designed the algorithm to improve connectivity.

(2) Control LSI corresponding to MAC sublayer and PLCP sublayer

The LSI is an SoC (System on Chip) device integrating CPU, memory, and AD/DA converters. It is a key device that provides data framing, time management, encryption, modulation/demodulation, and interfaces for MFPs and laser printers. Supported encryption schemes are WEP (ARC4), TKIP (ARC4), and CCMP (AES), and supported modulation/demodulation schemes are DBPSK, DQPSK, BPSK, QPSK, 16QAM, and 64QAM for primary modulation and DSSS/CCK and OFDM for secondary modulation. The architecture is optimized for MFPs and laser printers; rich functions and performance are integrated into one chip.

(3)Radio-frequency (RF) circuit corresponding to PMD sublayer

This circuit supports channels of the 2.4 GHz band and the 5 GHz band. Support for the 5 GHz band allows users to enjoy high-speed communications in an environment where interference waves are marginal. The circuit is approved under local regulations in many countries and regions – Japan, USA, Canada, Europe, China, and Taiwan. While the board is common to all countries and regions, it operates in accordance with radio wave restrictions of the shipping destinations.