Nortel Networks Corporation

Northern Telecom Limited

Nothern Telecom Limited

Saleh Faruque

Fereidoun Homayoun

Wing Fai Lo

Payam Maveddat

Mini Vasudevan

A low-cost data communication system and method using modems to provide high speed multi-class services to subscribers is disclosed. In the present invention, an n-bit orthogonal modulating code is uniquely partitioned into several subsets whereas each subset is assigned to a particular class of services. When data streams from different classes of services go through an encoding modem equipped with the partitioned orthogonal codes, they can be split based on their classes, encoded, modulated through a multilevel phase modulation simultaneously. Thereafter, since the encoded streams are orthogonal to each other, they can be combined as a composite modulated outgoing data stream and transmitted through a wired communication channel such as a cable or optical fiber channel. At a receiving end, a decoding modem can receive the encoding scheme from the encoding modem, and appropriately decode the transmitted information. This method enables sharing the same communication channel by multiple classes of services and processing different classes of information separately but simultaneously, and thus enhancing the overall performance of the shared communication channel.

High capacity robust modem for multiple classes of services

A system and method is disclosed for providing multiple classes of communication services on a high-speed, high capacity communication platform over Wave Division Multiplexing (WDM) networks. A predetermined set of light channels of a WDM network is partitioned into one or more sub groups based on their wavelengths, each sub group is assigned for providing exclusively one communication service such as video, audio or data communication services. Each light channel is modulated by a predetermined set of orthogonal codes so that neighboring channel interferences can be minimized. Further, the predetermined set of orthogonal codes can be further divided into an even group and an odd group. These two groups of codes are assigned to two immediate neighboring light channels. As an alternative, multiple light channels can share a single set of predetermined orthogonal codes provided a mechanism is implemented for a plurality of use terminals connected to the optical network to monitor available orthogonal code instantly.

Method and system for providing multiple classes of services in dense wavelength division multiplexing optical networks

A system and method is disclosed for providing high-speed, high capacity data communication over a Wave Division Multiplexing (WDM) network with an efficient re-routing capability. When all light channels between two nodes in the network are loaded with transmission jobs, a transmission traffic congestion is created. In order to avoid or alleviate the congestion, a new alternative route is needed. An alternative route is selected to direct the traffic away from the congested route, and further expand the channel capacity of the alternative route by encoding the light channels in the alternative route with orthogonal codes.

Method and system for alternative transmission traffic routing in dense wavelength division multiplexing optical networks

A low-cost data communication system using modems is disclosed. In the proposed system and method, a binary incoming data stream is split into several parallel sub streams by an encoding modem. These parallel sub streams are mapped into a set of unique orthogonal short-codes and then modulated by a bank of modulators. Thereafter, the modulated data are combined and transmitted through a wired communication channel such as a cable or optical fiber channel. Since there are no multipath components in cables or fiber optical communication channel, the composite outgoing data stream from the encoding modem remains orthogonal during the transmission and maximizes CDMA capacity. A decoding modem can receive encoding information from the encoding modem and appropriately decode the transmitted information.

Code division multiple access cable modem

A number of user IDs are assigned to each wireless device. The number of user IDs required is based on the type of information transmitted (e.g., video, voice, or data). The user ID's generate the orthogonal Walsh codes used to cover a data signal to be transmitted. Each Walsh code is 2,-bits in length and the memory size is 2,&times;2,where n is the number of bits in the Walsh code. Each unique user ID addresses a memory to generate a unique Walsh code corresponding only to that user ID. The orthogonal codes output from the memory cover the information to be transmitted. This results in the transmitted signal being orthogonal to other users and also orthogonal within the transmitting user's own signal bursts.

Broadband wireless access based on code division parallel access

The present invention assigns a pair of user ID's to each user. The user ID's are used as addresses to access two orthogonal Walsh codes in a memory. Each Walsh code is 2,-bits in length and the memory size is 2,&times;2,. The orthogonal codes are then used to cover the information symbols for transmission. This results in the transmitted signal being orthogonal to other users and also orthogonal within the transmitting user's own signal bursts.

Bi-orthogonal code division multiple access system

The fractional frequency reuse plan groups available frequencies into 16 frequency groups. These frequency groups are then allocated to a group of sectors such that a four by four matrix results. The top two rows of the matrix are alternating odd numbered frequency groups while the bottom two rows of the matrix are alternating even numbered frequency groups. This group of frequencies is then reused in such a way that three adjacent reuses of a frequency group forms an apex of a triangle. Each reuse on the triangle appears as back-to-back, radiating in different direction, 120.degree. apart. This frequency reuse plan generates an N=5.333 system.

High capacity cell planning based on fractional frequency reuse

The frequency transition process migrates frequency groups from one frequency reuse plan to another. In response to a change in capacity requirements, the process migrates each layer of the present frequency reuse plan to the layers of the new frequency reuse plan.

Frequency transition process for capacity enhancement in a cellular

The process of the present invention is based on a tri-cellular, hexagonal platform where six, or a multiple of six, frequency groups are directionalized and reused in the same direction. Directional antennas are located in the center of each tri-cell group. Each antenna radiates into a 120.degree. sector of the tri-cell group. The reused frequency groups are aligned along the 0.degree., 120.degree., and 240.degree. axes of each cell. Each axis has three layers, the two outer layers having an identical frequency reuse series. The frequency groups are reused in the same direction along each axis, reducing the number of dominant interfering cells to one.

N=4 directional frequency assignment in a cellular radio system

The present invention is based on a tri-cellular grouping of three identical cells. Each cell of the tri-cellular group is driven by a directional antenna that radiates the cell from the center of the group. Multiple tri-cellular groups make up a cellular system having three axes at 0.degree., 120.degree., and 240.degree.. Each axis is comprised of seven total layers, one layer being a repeat of another of the layers. The 512 available system PN offsets are divided up into three groups of 24 offsets, one group for each axis. Each PN offset group is reused only in the direction to which it is assigned.

Directional pseudonoise offset assignment in a CDMA cellular

The process of the present invention is based on a hexagonal cellular platform where six, or a multiple of six, frequency groups are directionalized and reused in the same direction. Directional antennas are located in the center of each cell. Each antenna radiates into a 60.degree. sector of the cell. The reused frequency groups are aligned along the 0.degree., 120.degree., and 240.degree. axes of each cell. Each axis has three layers, the two outer layers having an identical frequency reuse series. The frequency groups are reused in the same direction along each axis, reducing the number of dominant interfering cells to one.

Directional frequency assignment in a cellular radio system

A method for deploying a PCS system wherein radio transceivers are deployed at spacings which correspond to a diameter of a first Fresnel zone and set output powers of the transceivers to define cells which correspond to the first Fresnel zone of the transceivers. A PCS system having radio transceivers deployed at spacings corresponding to a diameter of a first Fresnel zone and operating at output powers which define cells corresponding to the first Fresnel zones of the transceivers. A handoff area surrounds the first Fresnel zone breakpoint.

Multipath tolerant cellular communication system and method

The process of the present invention is based on a tri-cellular platform where nine, or a multiple of nine, frequency groups are directionalized and reused in the same direction. Directional antennas are located in the center of the tri-cell group. Each antenna radiates into a 120.degree. sector of each cell, effectively radiating the entire cell from the corner. The reused frequency groups are aligned along the 0.degree., 120.degree., and 240.degree. axes of each tri-cell group. The frequency groups are reused in the same direction along each axis, reducing the number of dominant interfering cells to one.

Directional frequency allocation in an N=6 cellular radio system

The N=4 frequency layout plan of the present invention is based on dividing up the available frequencies into 12 or a multiple of 12 frequency groups. These groups are then distributed evenly and alternately among four tri-cell groups. Each tri-cell group is comprised of three identical cells that are driven by a single source located in the center of the tri-cell group. In the preferred embodiment, the frequency distribution is a horizontal distribution of first the odd frequencies then the even frequencies so that there are no adjacent channels.

Growing community of inventors

Plano, TX, United States of America

Saleh Faruque