A method for constructing a codebook in a multiple-antenna wireless communication system and an apparatus therefor are disclosed. Specifically, constructing a codebook in a multiple-antenna wireless communication system comprises the steps of: receiving parameters for constructing a codebook from a base station; and constructing a codebook using the parameters for constructing the codebook, wherein the parameters for constructing the codebook may include a phase value () of a first code vector forming the codebook, a phase difference () between code vectors that are adjacent to one another within the codebook, and the number of bits () that is required when feeding back a code vector selected thin the codebook.

A method for transmitting and receiving a codebook subset restriction bitmap is provided. The Codebook Subset Restriction (CSR) bitmap transmission method of an evolved Node B (eNB) in transmission mode 9 for communication with 8 antenna ports includes generating a CSR bitmap including bits corresponding to restricted precoding matrix indicators and rank indicators that are not allowed for reporting and transmitting the CSR bitmap to a User Equipment (UE). The CSR bitmap comprises 53 bits corresponding to a first codebook and 56 bits corresponding to a second codebook, the 53 bits corresponding to a first codebook comprise 16, 16, 4, 4, 4, 4, and 1 bits for layers 1, 2, 3, 4, 5, 6, 7, and 8, respectively, and the 56 bits corresponding to a second codebook comprise 16, 16, 16 and 8 bits for layers 1, 2, 3, and 4, respectively.

A content delivery system includes a cache server, a domain name server, and a redirector. The domain name server is configured to receive a request for a cache server address, and provide an IPv6 anycast address. The redirector is configured to receive a content request addressed to the IPv6 anycast address from a client system, receive load information from the cache server, and determine if the cache server is available. The redirector is further configured to forward the content request to the cache server when the cache server is available. The cache server is configured to receive the content request forwarded from the redirectors, send a response to the content request to a client system, the response including an IPv6 unicast address of the cache server as a source address, an IPv6 unicast address of the client system as a destination address, and the IPv6 anycast address as a home address, and provide the content to the requestor.

A method and apparatus for allowing a UE to transmit uplink signals using a MIMO scheme are disclosed. In order to maintain good Peak power to Average Power Ratio (PAPR) or Cubic Metric (CM) properties when the UE transmits uplink signals using the MIMO scheme, the UE uses a precoding scheme based on a precoding matrix established in a manner that one layer is transmitted to each antenna in specific rank transmission.

A method and apparatus for allowing a UE to transmit uplink signals using a MIMO scheme are disclosed. In order to maintain good Peak power to Average Power Ratio (PAPR) or Cubic Metric (CM) properties when the UE transmits uplink signals using the MIMO scheme, the UE uses a precoding scheme based on a precoding matrix established in a manner that one layer is transmitted to each antenna in specific rank transmission.

A method for transmitting and receiving uplink signals using an optimized rank 3 codebook is disclosed. The optimized rank 3 codebook includes 6 precoding matrix groups, each of which has 1 variable having an amplitude of 1. Preferably, the optimized 4Tx rank 3 codebook has 12 precoding matrix, two precoding matrixes are selected from each the above 6 precoding matrix groups considering chordal distance and the number of precoding matrix.

Methods and apparatuses for CSI reporting mechanisms are provided. A user equipment (UE) includes a transceiver and a processor operably connected to the transceiver. The transceiver is configured to receive channel state information (CSI) process configuration information including at least one beamformed type associated with a plurality of non-zero-power (NZP) CSI reference signal (CSI-RS) resource configurations and receive a CSI-RS resource index (CRI) reporting configuration. The processor is configured to calculate, in response to receipt of the configuration information, a CRI and a channel quality indicator (CQI). The transceiver is further configured to report the CRI and the CQI by transmitting the CRI and the CQI on an uplink channel.

An apparatus for mapping data in a wireless communication system. The apparatus includes circuitry for generating a precoding matrix for multi-antenna transmission based on a precoding matrix indicator (PMI) feedback from at least one remote receiver where the PMI indicates a choice of precoding matrix derived from a matrix multiplication of two matrices from a first code book and a second codebook. The apparatus further includes circuitry for precoding one or more layers of a data stream with the precoding matrix and transmitting the precoded layers of data stream to the remote receiver.

A method of wireless communication includes determining a first precoding matrix indicator (PMI) value and a second PMI value, the first PMI value indicating a first matrix W1 of a first codebook C1, the second PMI value indicating a second matrix W2 of a second codebook C2, wherein the first matrix W1 and the second matrix W2 together define a precoding matrix W for multi-antenna transmission. The method also includes transmitting the first PMI value at a first periodicity, and transmitting the second PMI value at a second periodicity shorter than the first periodicity. In some examples, the method also includes transmitting a rank indicator (RI) value, where the first PMI value and the second PMI value are determined based on the RI value.