Abstract:
A method and system for wireless communication with a mobile device in which wireless communication is established with the mobile device. A base station is used to transmit directly to the mobile device in a downlink direction. A relay node is used to transmit to the base station communications received in an uplink direction from the mobile station. The relay node relays at least a portion of the uplink traffic received from the mobile station to the base station.
Abstract:
In some embodiments of the invention, OFDM symbols are transmitted as a plurality of clusters. A cluster includes a plurality of OFDM sub-carriers in frequency, over a plurality of OFDM symbol durations in time. Each cluster includes data as well as pilot information as a reference signal for channel estimation. In some embodiments, a plurality of clusters collectively occupy the available sub-carrier set in the frequency domain that is used for transmission. In some embodiments of the invention data and/or pilots are spread within each cluster using code division multiplexing (CDM). In some embodiments pilots and data are separated by distributing data on a particular number of the plurality of OFDM symbol durations and pilots on a remainder of the OFDM symbol durations. CDM spreading can be performed in time and/or frequency directions.
Abstract:
Methods and systems are provided that enable an OFDM transmitter to be used for transmitting conventional OFDM or a form of transformed OFDM. A technique is provided for transforming a coded and modulated sequence of samples prior to an IFFT that enables the transformed sequence of samples to be transmitted using conventional OFDM or transformed OFDM. The selection of a transform function for transforming the coded and modulated sequence of samples may be based on optimizing the transform function for particular operating conditions between the transmitter and receiver. In some embodiments of the invention OFDM and time transformed OFDM are multiplexed in time and/or frequency in a transmission frame. In some embodiments of the invention a pilot pattern is provided in which the pilot are sent using OFDM and data is sent using OFDM and/or transformed OFDM.
Abstract:
A method and apparatus for improving channel estimation within an OFDM communication system. Channel estimation in OFDM is usually performed with the aid of pilot symbols. The pilot symbols are typically spaced in time and frequency. The set of frequencies and times at which pilot symbols are inserted is referred to as a pilot pattern. In some cases, the pilot pattern is a diagonal-shaped lattice, either regular or irregular. The method first interpolates in the direction of larger coherence (time or frequency). Using these measurements, the density of pilot symbols in the direction of faster change will be increased thereby improving channel estimation without increasing overhead. As such, the results of the first interpolating step can then be used to assist the interpolation in the dimension of smaller coherence (time or frequency).
Abstract:
A method and system for wireless communication with a mobile device in which wireless communication is established with the mobile device. A base station is used to transmit directly to the mobile device in a downlink direction. A relay node is used to transmit to the base station communications received in an uplink direction from the mobile station. The relay node relays at least a portion of the uplink traffic received from the mobile station to the base station.
Abstract:
The present application provides methods, devices and transmitters that mitigate increases in peak to average power ratio (PAPR) from transmission diversity in a single carrier frequency division multiple access (SC-FDMA) modulated uplink. A PAPR preserving precode matrix hopping method that utilizes cyclic shift delays is provided, as well as a sub-band based transmit diversity scheme. The present application also provides methods, devices and transmitters that relax the scheduling restrictions associated with uplink scheduling in the LTE standard.
Abstract:
A method and apparatus for improving channel estimation within an OFDM communication system. Channel estimation in OFDM is usually performed with the aid of pilot symbols. The pilot symbols are typically spaced in time and frequency. The set of frequencies and times at which pilot symbols are inserted is referred to as a pilot pattern. In some cases, the pilot pattern is a diagonal-shaped lattice, either regular or irregular. The method first interpolates in the direction of larger coherence (time or frequency). Using these measurements, the density of pilot symbols in the direction of faster change will be increased thereby improving channel estimation without increasing overhead. As such, the results of the first interpolating step can then be used to assist the interpolation in the dimension of smaller coherence (time or frequency).
Abstract:
Methods and systems for providing efficient communications between two mobile stations served by the same base station or relay station are provided. A base station maintains information identifying which mobile stations it is serving. When a connection is set up between two mobile stations, if they are both being served by the same base station, the base station forwards traffic directly between the two mobile stations without forwarding it on to higher level network entities.
Abstract:
Aspects of the invention include methods and devices for inserting data and pilot symbols into Orthogonal Frequency Division Multiplexing (OFDM) frames having a time domain and a frequency domain. A method involves inserting in at least one zone of a first type a two dimensional array of data and pilot symbols in time and frequency and inserting in at least one zone of a second type a two dimensional array of data and pilot symbols in time and frequency. In some implementations the zone of the first type comprises common pilot symbols that can be detected by all receivers receiving the OFDM frame. In some implementations the zone of the second type comprises dedicated pilot symbols that are only detectable by a receiver that is aware of pre-processing used to encode the dedicated pilot symbols.
Abstract:
A method and system for allocating shareable wireless transmission resources. A resource pool is established. The resource pool is divided into a plurality of physical layer allocation units usable for wirelessly transmitting control information and traffic data. The allocation units are assigned at the media access control layer for the wireless transmission of the control information and traffic data. The system and method of the present invention also allows mobile stations to be dynamically grouped into multicast groupings to reduce system overhead resource requirements.