Mitsubishi

About: Mitsubishi is a company organization based out in Tokyo, Japan. It is known for research contribution in the topics: Layer (electronics) & Signal. The organization has 53115 authors who have published 54821 publications receiving 870150 citations. The organization is also known as: Mitsubishi Group of Companies & Mitsubishi Companies.

Forward error correction based on block turbo code with 3-bit soft decision for 10-Gb/s optical communication systems

Abstract: The first experimental demonstration of a forward error correction (FEC) for 10-Gb/s optical communication systems based on a block turbo code (BTC) is reported. Key algorithms, e.g., extrinsic information, log-likelihood ratio, and soft decision reliability, are optimized to improve the correction capability. The optimum thresholds for a 3-bit soft decider are investigated analytically. A theoretical prediction is verified by experiment using a novel 3-bit soft decision large scale integrated circuit (LSI) and a BTC encoder/decoder evaluation circuit incorporating a 10-Gb/s return-to-zero on-off keying optical transceiver. A net coding gain of 10.1 dB was achieved with only 24.6% redundancy for an input bit error rate of 1.98/spl times/10/sup -2/. This is only 0.9 dB away from the Shannon limit for a code rate of 0.8 for a binary symmetric channel. Superior tolerance to error bursts given by the adoption of 64-depth interleaving is demonstrated. The ability of the proposed FEC system to achieve a receiver sensitivity of seven photons per information bit when combined with return-to-zero differential phase-shift keying modulation is demonstrated.

Heat treatment jig for silicon semiconductor substrate

Abstract: A heat treatment jig for supporting silicon semiconductor substrates by contacting, being loaded onto a heat treatment boat in a vertical heat treatment furnace, comprises; the configuration of a ring or a disc structure with the wall thickness between 1.5 and 6.0 mm; the deflection displacement of 100 μm or less at contact region in loaded condition; the outer diameter which is 65% or more of the diameter of said substrate; and the surface roughness (Ra) of between 1.0 and 100 μm at the contact region. The use of said jig enables to effectively retard the slip generation and to avoid the growth hindrance of thermally oxidized film at the back surface of said substrate, diminishing the surface steps causing the defocus in photolithography step in device fabrication process, thereby enabling to maintain high quality of silicon semiconductor substrates and to substantially enhance the device yield.

Semiconductor device and module

Abstract: A semiconductor device in a vertical surface mount package, reduced in size and having a higher heat radiating capacity, a method of producing the semiconductor device, and a semiconductor module. Leads of a first lead frame and leads of a second lead frame are parallel to each other and at least a portion of the leads overlap leads of the other lead frame when geometrically projected on them. An inner lead may extend out from the semiconductor package or the back side of a die pad in the semiconductor package may be exposed. The invention allows more outer leads to be used and makes it possible to reduce the size of the semiconductor device and to achieve high density mounting.

Adaptive Soft Frequency Reuse for Inter-Cell Interference Coordination in SC-FDMA Based 3GPP LTE Uplinks

Abstract: This paper proposes a decentralized adaptive soft frequency reuse scheme for the uplink of 4G long-term evolution (LTE) systems. While universal frequency reuse (UFR) is being targeted for next generation multi-cellular wireless networks, ongoing efforts supporting the LTE standard have proved that actual implementations of UFR in LTE lead to unacceptable interference levels experienced by user equipments near the cell edge area in a multi-cellular configuration. The herein proposed adaptive soft frequency reuse scheme is a step forward towards effective inter-cell interference coordination (ICIC) in next-generation wireless networks. Our solution to the uplink ICIC problem stands out for its two essential features that consist of physical resource block (PRB) reuse avoidance/minimization and cell-edge bandwidth breathing which can be implemented at the cost of a negligible information exchange over the X2 interface (backbone). The PRB reuse avoidance feature significantly decreases inter-cell interference levels while improving the achievable average throughput per user, especially for those identified as cell-edge ones. The cell-edge bandwidth breathing strategy allows to track and adapt to semi-static changes in traffic loading and user distributions within each cell which drastically reduces the blocking probability of incoming calls under cell-edge bandwidth constrained traffic.