Nortel Networks Corporation

Apple Inc.

Rockstar Bidco, LP

Northern Telecom Limited

Keith S Wilson

Fiona Wilson

Martin Stevens Smith

Andrew William Jeffries

Christopher Robert Ward

John Edward Hudson

Julius Robson

Srinivas Eswara

Chris Ward

Michael John McCarthy

Mark Watkins

D Damian N Bevan

A base station for wireless network uses one or more MIMO channels having subchannels, to communicate with multiple user equipments, and allocates the sub channels to the user equipments. Different subchannels of a given one of the channels can be allocated to different user equipments. The ability to allocate sub channels individually rather than only allocating entire channels can enable higher data rates to be achieved. This is particularly useful for improving data rates at cell boundaries or sector boundaries, where the coverage is traditionally weakest. A user equipment can use subchannels from different MIMO channels from different sectors or from different base stations.

Allocation of sub-channels of MIMO channels using a basestation with plurality of sectors

Allocation of sub-channels of MIMO channels using a basestation with a plurality of sectors

Allocation of sub channels of MIMO channels of a wireless network

A base station for wireless network uses one or more MIMO channels having subchannels, to communicate with multiple user equipments, and allocates the sub channels to the user equipments. Different subchannels of a given one of the channels can be allocated to different user equipments. The ability to allocate sub channels individually rather than only allocating entire channels can enable higher data rates can be achieved. This is particularly useful for improving data rates at cell boundaries or sector boundaries, where the coverage is traditionally weakest. A user equipment can use subchannels from different MIMO channels from different sectors or from different base stations.

The invention relates to improving the quality of a received downlink signal in a time division multiple access wireless cellular communications network. The method of the invention comprises measuring a signal quality characteristic at a user equipment and comparing this to a threshold to determine it a desired signal quality level exists. It so then a certain level or type of service on the downlink can be effected. It not, the method comprises identifying an interferer signal or signals and removing at least one of such interferer signals by arranging for it to either not be transmitted on the same TDMA timeslot as the downlink signal or to be transmitted at a lower power, for example, in said timeslot.

Method and apparatus for improving a transmission signal characteristic of a downlink signal in a time division multiple access wireless communication system

Spatial Division Multiple Access (SDMA) offers multiplicative spectral efficiency gains in wireless networks. An adaptive SDMA beamforming technique is capable of increasing the traffic throughput of a sector, as compared to a conventional tri-cellular arrangement, by between 4 and 7 times, depending on the environment. This system uses an averaged covariance matrix of the uplink signals received at the antenna array to deduce the downlink beamforming solution, and is equally applicable to Frequency Division Duplex (FDD) and Time Division Duplex (TDD) systems. A scheduling algorithm enhances the SDMA system performance by advantageously selecting the users to be co-scheduled.

Downlink beamforming for broadband wireless networks

Space division multiple access scheduling for a transmitter having an antenna array with multiple beams includes determining, and storing at the transmitter, angles of arrival of signals and identifiers from user equipments, such as cellular telephones. The user equipment identifiers are sorted at the transmitter in order of angle of arrival to form an ordered list. The ordered list is subdivided into ordered sub-lists of user equipment identifiers in order of angle of arrival. The transmitter sequentially transmits simultaneously to a group of each respective ordinal member of each sub-list of user equipments, which are well-spaced.

Space division multiple access scheduling

Methods of improving channel estimation are described, in which pilot symbols are inserted into orthogonal frequency division multiplexing (OFDM) frames at an OFDM transmitter having at least one transmitting antenna, wherein for the or each antenna, historical data regarding channel conditions is obtained so that the scattered pilot symbols are inserted in a scattered pattern dependent upon said historical data. Alternatively, or in addition, an adaptive channel estimation filter is used whose parameters are selected according to analysis of historical data regarding channel conditions.

Scattered pilot and filtering for channel estimation

A base station for a wireless network has multiple channels for communicating with user equipments, and has multiple channel reuse patterns. The patterns are complementary such that areas of low carrier to interference ratio C/I of one pattern are not coincident with areas of low C/I of other patterns. An allocator allocates channels such that for user equipment located in an area of low C/I of any of the complementary patterns, the allocator favors allocation of a channel of another of the complementary patterns. The sacrifice of capacity can be reduced as there is less need for a capacity-hungry high re-use factor pattern. The channels may be frequencies, time slots or CDMA codes. The reuse patterns can involve reuse on selected base stations, or on selected sectors, or different polarizations. The network can be of any type including fixed wireless access FWA, or mobile networks.

Multiple reuse patterns for channels of wireless networks

Provided is an apparatus adapted to transmit a first channel on at least two adjacent fixed beams of a plurality of fixed beams defining a coverage area, with each pair of adjacent fixed beams of the plurality of fixed beams partially overlapping and having substantially orthogonal polarizations. The apparatus has a respective transmitter adapted to transmit on each of the plurality of fixed beams a respective unique composite signal, each composite signal containing said first channel and a respective unique traffic channel.

Wireless transmitter, transceiver and method

Disclosed is an apparatus for reducing the number of control signal channels required in a wireless communication system by using a umbrella control signal to initially communicate with an MS (mobile station) within the umbrella and to assign the MS to a traffic frequency corresponding to one of a plurality of antenna used to cover the area covered by said umbrella control signal. Logic is used in combination with measured relative signal strengths to determine the position of the MS relative to the reliable reception coverage area of each of the plurality of antennas before the assignment is made.

Narrow beam traffic channel assignment method and apparatus

A frequency allocation method for allocating carrier frequencies to a plurality of fixed beams in a cellular radio based transceiver station comprises maintaining a reserve pool of carrier frequencies, such that any available carrier frequency can be allocated to any fixed beam at any one time in order to deal with capacity demands from mobile stations within an area covered by a fixed beam. A frequency allocation algorithm operates such as to allow a plurality of transceivers to float anywhere across a plurality of fixed directional beams. More carrier frequencies can be added to a beam to deal with increased mobile station capacity demand. The occupancy of channels on the carrier frequencies is continuously monitored, and the number of carrier frequencies per beam is continuously monitored, with the object of releasing unused carrier frequencies to a reserve pool of carrier frequencies, allowing re-deployment of unused carrier frequencies to other beams where necessary. Carrier frequencies are periodically 'groomed' by assessing the number of vacant channels on the carrier, and reallocating any un-utilized vacant channels to other carrier frequencies. The grooming process can be constrained to operate during natural gaps in speech, to avoid channel degradation.

Floating transceiver assignment for cellular radio

The present invention relates to a radio communications base station antenna. In a first embodiment, the arrangement comprises a plurality of antennas each capable of forming a separate narrow beam in azimuth, wherein the antennas are positioned such that the beams formed by the antennas overlap and the centre of each beam falls midway between the centre and first null of the adjacent beam to provide a uniform coverage in azimuth. The present invention can be deployed in mobile wireless terminals. The use of downlink beam-forming is proposed for systems such as Digital AMPS (D-AMPS). A downlink beam-former typically consists of a number of narrow beams formed by either multiple narrow beamwidth antennas or an array of elements in conjunction with a fixed beam-former. Signal processing techniques can then be used to select an appropriate beam directed towards the subscriber.

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Bishops Stortford, United Kingdom

Keith S Wilson