Kazuyoshi Oshima

Proposal of networking by PON technologies for full and ethernet services in FTTx

The construction of optical access networks is one of key issues to provide new broad-band services and emulation of legacy services. Passive optical network (PON) technologies realize sophisticated and economical optical access networks for these purposes. This paper summarizes requirements and technical and marketing trends for optical access networks. It also presents advantages of networking by PON technologies for optical access networks. Moreover, it clarifies issues to install and operate PON base optical access networks and proposes solutions for these issues.

622 Mb/s 8/spl times/8 shared multibuffer ATM switch with hierarchical queueing and multicast functions

A new ATM switch architecture, named the shared multibuffer architecture, features great advantages in the access speed, overall size of the buffer memories, and the cell loss performance. We have developed a 622 Mb/s 8/spl times/8 shared multibuffer ATM switch with multicast and hierarchical queueing functions to accommodate 156 Mb/s, 622 Mb/s and 2.4 Gb/s interfaces. Implementation of the shared multibuffer ATM switch is described with respect to four sorts of 0.8-/spl mu/m BiCMOS LSIs and an ATM switch board. The switch board consists of four aligner-LSIs, nine buffer-LSIs and one control-LSI (or control/type 2-LSI). Possible applications to an ATM access system and a 2.4 Gb/s ATM loop system are also discussed.<<ETX>>

Pilot-Based CSI Feedback in TDD/MIMO Systems with Cochannel Interference

This paper proposes a pilot-based channel state information (CSI) feedback in time-division duplex (TDD) / multi-input multi-output (MIMO) system, which enables the transmitter to perform transmit beamforming considering the receivers interference. In the proposed method, the receiver sends reverse-link pilot signals spatially prefiltered by linear precoder dependent on the receivers interference characteristics. The transmitter exploits responses of the reverse-link pilot signals to perform transmit beamforming considering the receivers interference. The transmitter also predicts the receivers output signal-to-interference-plus-noise power ratio (SINR) for each data stream. From simulation results, it is found that the transmitter achieves efficient transmission performance maintaining small control errors based on the proposed CSI feedback.

Pilot-Based Channel Quality Reporting for OFDMA/TDD Systems with Cochannel Interference

This paper proposes a new uplink signalling to report the terminals channel quality in multiple subbands to the base station (BS) using channel reciprocity in orthogonal frequency division multiple access / time division duplex (OFDMA/TDD) systems. In the proposed method, the terminal transmits uplink pilot signals in the subbands with different transmit power which is inversely proportional to the subband- based interference-plus-noise power. The BS can obtain knowledge of the terminals received signal-to-interference-plus-noise power ratio (SINR) on subband basis, measuring the pilot signal power. In performance evaluation, accuracy of the channel quality reporting and amount of the control signalling are examined. From numerical results, it is found that the proposed method becomes effective as the number of subbands and terminals for channel quality reporting increases.

Downlink Spatial Scheduling with Mutual Interference Cancellation in Multiuser MIMO Systems

This paper presents downlink spatial scheduling which nullifies interference among multiplexed signals perfectly in multiuser MIMO systems. Under the base stations zero-forcing transmit beamforming, each terminal can receive packet of interest without interference from the other multiplexed packets. The scheduling algorithm successively selects appropriate terminals for packet transmission in the presence of already selected packets. We show that the downlink spatial scheduler is equivalent to the virtual uplink spatial scheduler in terms of received signal characteristics. Applying the uplink scheduling concept to downlink, the downlink spatial scheduler achieves much higher system throughput than the system without spatial scheduling. Also, it is shown that the spatial scheduler has similar system throughput in uplink and downlink

An architecture for connectionless data service in B-ISDN

A method for the support of a direct B-ISDN (broadband integrated services digital network) connectionless service is proposed. The method has the advantages of eliminating the load to call control function, a small routing decision delay, simple routing control, and efficient use of virtual connections. The method is compared with the virtual ring method, which is proposed by the CCITT as an example of the direct provision of connectionless service, in terms of the traffic load within the network and the processing load in the connectionless service function. It is shown that the proposed method is suitable for a large-scale network and can be advantageously used when the number of cells associated with a packet is large.<<ETX>>

A 622 Mb/s 32/spl times/32 scalable shared buffer ATM switch with searchable address queue

The advanced 0.5-/spl mu/m CMOS technology makes it possible to integrate a huge amount of memories and enables us to apply sophisticated architecture. The implementation of the ATM switch chipset, using new architectures named funnel-structured expandable architecture and the searchable address queueing scheme, is described. A 622 Mb/s 32/spl times/8 element switch consists of one buffer LSI and one control LSI. A 622 Mb/s 32/spl times/32 switch which comprises four element switches can be installed in one board. The switch has delay-priority control, cell-loss priority control, multicasting function and hierarchical queueing function to accommodate 156 Mb/s, 622 Mb/s and 2.4 Gb/s interfaces.