Abstract: A method and apparatus are described for minimizing inter-cell interference at multiple wireless transmit/receive units (WTRUs) using a shared node (SN). Each WTRU may be configured to receive a desired signal transmitted by a base station in a cell combined with interfering signals transmitted by other base stations in other cells in a first transmission time interval (TTI), and a precoded signal transmitted by the SN in a second TTI. The WTRUs may buffer the desired and interfering mixed signals received in the first TTI, and then combine the buffered signals with the precoded signal received in the second TTI to minimize the interfering signal's power and maximize the desired signal's power at each WTRU so that the desired signal may be decoded with higher probability. The SN may generate the precoded signal based on codewords or codeword components transmitted by the base stations in the same resource blocks.

Abstract: Embodiments contemplate channel access systems and methods for cognitive relaying in unlicensed and lightly licensed bands. Embodiments contemplate managing nodes of a wireless network operating in an unlicensed and or lightly licensed band. One or more embodiments may include sensing an idle channel in the unlicensed and/or lightly licensed band. Further, embodiments contemplate using the idle channel for wireless communication.

Abstract: A wireless communication network and method are described for enhancing cell-edge performance of a wireless transmit/receive unit (WTRU). The WTRU may establish a connection with a plurality of sites via respective downlinks (DLs). Each DL may include at least one DL component carrier (CC) that operates on a frequency that is the same or different than one or more of the other CCs. The sites may manipulate their transmit power for a particular CC operating frequency such that the distance from a particular one of the sites to its cell boundary may become larger by increasing its transmit power on the particular frequency, and the distance from at least one of the other sites to its respective cell boundary may become smaller by decreasing its transmit power on the particular frequency. Thus, a coverage overlap between different CC frequencies may be created while maintaining a frequency reuse pattern of one.

Abstract: A method for reporting power headroom is disclosed. Power headroom may be reported across all carriers (wideband), for a specific carrier, or for a carrier group. The formula used to calculate the power headroom depends on whether the carrier (or a carrier in the carrier group) has a valid uplink grant. If the carrier or carrier group does not have a valid uplink grant, the power headroom may be calculated based on a reference grant. The power headroom is calculated by a wireless transmit/receive unit and is reported to an eNodeB.

Abstract: A method and apparatus for a wireless transmit receive unit (WTRU) to use a contention-based uplink communications channel, applies a rule-based restriction of access to the contention-based uplink channel that attempts to use at least one contention-free uplink channel allocation for uplink transmissions on a condition that at least one contention-free uplink channel allocation has been granted.

Abstract: A method and apparatus for determining uplink power in a wireless transmit receive unit (WTRU). The WTRU operates in a carrier aggregated system. The WTRU is configured to receive a plurality of uplink power parameters indexed to one of a plurality of uplink carriers and receive a transmit power control command indexed to the one of the plurality of uplink carriers. The WTRU is configured to determine a pathloss of the one of the plurality of uplink carriers and determine a transmit power for the one of the plurality of uplink carriers based on the plurality of power parameters, the transmit power control command, and the pathloss.

Abstract: A method and apparatus are described for obtaining port index information. In one scenario, downlink (DL) control information (DCI) is received that includes new data indicator (NDI). The NDI has a value indicating an antenna port for single-port transmission. In response to receiving the DCI, a single-port transmission associated with the indicated antenna port is received. The NDI may be associated with a disabled codeword and the DCI may include a second NDI. The DCI may be received over a physical downlink control channel (PDCCH). The DCI may include a resource block (RB) assignment information field (IF), a hybrid automatic repeat request (HARQ) process identity (ID) IF, a transmit power control (TPC) IF and, for each of a plurality of transport blocks, a modulation and coding scheme (MCS), an NDI and a redundancy version (RV).

Abstract: Discontinuous reception (DRX) operations for wireless communications implementing carrier aggregation are disclosed. Physical downlink control channel implementation for carrier aggregation is also disclosed. DRX methods are disclosed including a common DRX protocol that may be applied across all component carriers, an individual/independent DRX protocol that is applied on each component carrier, and hybrid approaches that are applied across affected component carriers. Methods for addressing the effects of loss of synchronization on DRX, impact of scheduling request on DRX, uplink power control during DRX, and DRX operation in measurement gaps are disclosed.

Abstract: Methods and apparatus for random access in multicarrier wireless communications are disclosed. Methods and apparatus are provided for physical random access channel (PRACH) resource signaling, PRACH resource handling, preamble and PRACH resource selection, random access response (RAR) reception, preamble retransmission, and transmission and reception of subsequent messages. A method for maintaining an allowed multicarrier uplink (UL) random access channel (RACH) configuration set by adding an UL carrier to the allowed RACH configuration set provided that a triggering event occurs and performing a random access (RA) procedure using the allowed RACH configuration set. A method for sending data in multicarrier wireless communications by determining a set of available UL carriers and selecting an UL carrier from the set of available UL carriers.

Abstract: A method and apparatus for signal processing in a wireless transmit receive unit (WTRU), including generating a plurality of data bits and a plurality of control bits, mapping the data bits and control bits to one or more codewords, multiplexing the data bits and control bits, dividing the bits into layers, allocating control bits to each layer based on a channel quality of each codeword and a channel quality of each layer, and channel interleaving each layer for output to one or more antennas.

Abstract: A method and apparatus for handling a control channel for carrier aggregation in wireless communications. The method includes determining which component carrier to listen to, detecting the downlink control channel, processing mapping information related to downlink and uplink transmissions and operating discontinuous reception with respect to carrier aggregation. The method also includes detecting a component carrier, determining the component carrier type and locating the anchor component carrier, if necessary, where the anchor component carrier carries the carrier aggregation information.

Abstract: A method and apparatus for applying network coding in multi-user (MU) multiple-input multiple-output (MIMO) control signaling are disclosed. After a pair of wireless transmit/receive units (WTRUs) transmit channel state information (CSI) to an evolved Node-B (eNodeB), each of the WTRUs receive network coded information from the eNodeB, including the CSI transmitted by both of the WTRUs, and decode the network coded information. The WTRUs transmit CSI on a scheduled basis, and store CSI that was previously transmitted. Each of the WTRUs measure the amount of time that pass since they transmitted CSI, and use the transmitted CSI to decode the network coded information on the condition that the measured time does not exceed a predetermined threshold. If the measured time exceeds the predetermined threshold, the stored CSI is used to decode the network coded information.

Abstract: A method for reporting power headroom is disclosed. Power headroom may be reported across all carriers (wideband), for a specific carrier, or for a carrier group. The formula used to calculate the power headroom depends on whether the carrier (or a carrier in the carrier group) has a valid uplink grant. If the carrier or carrier group does not have a valid uplink grant, the power headroom may be calculated based on a reference grant. The power headroom is calculated by a wireless transmit/receive unit and is reported to an eNodeB.

Abstract: A method and apparatus for transmitting and receiving orthogonal frequency division multiplex (OFDM)-based transmissions are disclosed. Control information may be transmitted at least one symbol prior to the corresponding data symbols so that a wireless transmit/receive unit (WTRU) has time to determine which parts of the subcarriers need to be received without having to buffer any corresponding data symbols. Control information related to frequency location of the data may be received in the first subframe and control information not related to the frequency location of the data may be received in the second subframe that includes the corresponding data. The offset between the control information and the data may be a fixed value, may be received from the network, or may be included in the control information preceding the corresponding data.

Abstract: A method and apparatus for transmitting uplink control information (UCI) for Long Term Evolution-Advanced (LTE-A) using carrier aggregation is disclosed. Methods for UCI transmission in the uplink control channel, uplink shared channel or uplink data channel are disclosed. The methods include transmitting channel quality indicators (CQI), precoding matrix indicators (PMI), rank indicators (RI), hybrid automatic repeat request (HARQ) acknowledgement/non-acknowledgement (ACK/NACK), channel status reports (CQI/PMI/RI), source routing (SR) and sounding reference signals (SRS). In addition, methods for providing flexible configuration in signaling UCI, efficient resource utilization, and support for high volume UCI overhead in LTE-A are disclosed.

Abstract: A method and apparatus are described for providing improved channel estimation for wireless transmit/receive units (WTRUs) that require improved channel estimation (e.g., cell edge WTRUs) by allocating additional resource elements (REs) as pilot signals to improve channel estimation. These additional REs may be allocated to be used with expanded reference signals (ERSs).

Abstract: A method and system switches antennas in an orthogonal frequency division multiplexed access (OFDMA) wireless communication system while transmitting symbols. Each symbol includes a cyclic prefix and a block of data signals. The symbols are transmitted during a first portion of a transmission time interval (TTI), from a first antenna. Then, the RF chain is switched to a second antenna to transmit the symbols, and in which the switching is performed substantially between transmitting two consecutive transmitted symbols.

Abstract: A method and apparatus are provided for multi-cell cooperation when multiple cells are cooperating to transmit data to a plurality of wireless transmit/receive units (WTRUs), and each cell is using a common precoding matrix. The level of information exchanged among the cells may depend on the particular cooperation architecture. The cells may share information such as channel state information (CSI), a channel quality indicator (CQI), or both. The cells may share rank indications reported by the WTRUs. The cells may also share the data that is being transmitted to the WTRUs. The method and apparatus may also determine precoding vectors for closed-loop precoding; a CQI, CSI and rank, and distributed space-time/frequency coding with multi-cell cooperation. The method and apparatus may also perform hybrid automatic repeat request (HARQ) with multi-cell cooperation, and downlink control signaling.

Abstract: Methods for signaling precoding matrices used at the Node-B for data transmission with multiple user-multiple in multiple out (MU-MIMO) wireless communications. Precoding vectors may be efficiently signaled between wireless transmit/receive units and base stations using control channels, reference signals and blind detection of the precoding information.

Abstract: A method and an apparatus for performing multiple-input multiple-output (MIMO) wireless communications are disclosed. A Node-B may receive an index to a pre-coding matrix in a single user MIMO (SU-MIMO) pre-coding codebook from wireless transmit/receive units (WTRUs) and adaptively perform one of SU-MIMO or multi-user MIMO (MU-MIMO) based on a predetermined criterion. Channel information for performing MU-MIMO may be obtained based on the pre-coding matrix of the SU-MIMO pre-coding codebook. A rank requested by the WTRU may be overridden if the unitary MU-MIMO codebook is a subset of the SU-MIMO pre-coding codebook. If not, a MU-MIMO pre-coding matrix with a largest correlation to the pre-coding matrix may be selected. A WTRU may send a pre-coding matrix for transmission to the WTRU along with a preferred interference matrix. A WTRU may send rank information and multiple right singular vectors for MU-MIMO.