摘要:
Techniques for transmitting information using beacon symbols are described. A transmitter may map first information to at least one subcarrier in a first set of subcarriers, with the first information being conveyed by the position of the at least one subcarrier. The transmitter may map second information to one or more subcarriers in a second set of subcarriers. The second information may be conveyed by one or more modulation symbols sent on the one or more subcarriers. The transmitter may generate at least one beacon symbol having the first information mapped to the at least one subcarrier in the first set and the second information mapped to the one or more subcarriers in the second set. In one design, the transmitter may frequency division multiplex the first information with the second information. In another design, the transmitter may puncture the second information on the at least one subcarrier with the first information.
摘要:
In a single-carrier frequency division multiple access (SC-FDMA) system, a receiver receives transmission symbols from a transmitter, determines a set of subbands used by the transmitter, processes the received transmission symbols for the set of subbands, obtains received pilot values for a transmitted pilot, and obtains received data values for transmitted data. The receiver may iteratively perform channel and interference estimation for the transmitter. The receiver selects an initial interference estimate, derives a channel estimate based on the received pilot values and the interference estimate, and derives a new interference estimate based on the received pilot values and the channel estimate. The receiver may repeat the derivation of the channel estimate and the interference estimate for multiple iterations. The receiver then performs data detection and/or receiver spatial processing on the received data values based on the channel estimate and the interference estimate.
摘要:
In a single-carrier frequency division multiple access (SC-FDMA) system that utilizes interleaved FDMA (IFDMA) or localized FDMA, multiple transmitters may transmit their pilots using time division multiplexing (TDM), code division multiplexing (CDM), interleaved frequency division multiplexing (IFDM), or localized frequency division multiplexing (LFDM). The pilots from these transmitters are then orthogonal to one another. A receiver performs the complementary demultiplexing for the pilots sent by the transmitters. The receiver may derive a channel estimate for each transmitter using an MMSE technique or a least-squares technique. The receiver may receive overlapping data transmissions sent on the same time-frequency block by the multiple transmitters and may perform receiver spatial processing with spatial filter matrices to separate these data transmissions. The receiver may derive the spatial filter matrices based on the channel estimates for the transmitters and using zero-forcing, MMSE, or maximal ratio combining technique.
摘要:
A receiver for receiving a pilot generated based on a polyphase sequence having a constant time-domain envelope and a flat frequency spectrum is disclosed. In one design, the receiver includes at least one demodulator and at least one processor. The demodulator(s) receive at least one single-carrier frequency division multiple access (SC-FDMA) symbol transmitted via a communication channel and including pilot symbols generated based on a polyphase sequence. The demodulator(s) remove a cyclic prefix in each SC-FDMA symbol and demodulate the at least one SC-FDMA symbol to obtain received pilot symbols. The processor(s) derive a channel estimate for the communication channel based on the received pilot symbols.
摘要:
Techniques for transmitting and detecting for overhead channels and signals in a wireless network are described. In an aspect, a base station may blank (i.e., not transmit) at least one overhead transmission on certain resources in order to detect for the at least one overhead transmission of another base station. In one design, the base station may (i) send the overhead transmission(s) on a first subset of designated resources and (ii) blank the overhead transmission(s) on a second subset of the designated resources. The designated resources may be resources on which the overhead transmission(s) are sent by macro base stations. The base station may detect for the overhead transmission(s) from at least one other base station on the second subset of the designated resources. In another aspect, the base station may transmit the overhead transmission(s) on additional resources different from the designated resources.
摘要:
Systems and methodologies are described that facilitate blanking on portions of bandwidth utilized by communicating devices that are dominantly interfered by a disparate device in wireless communications networks. The portions of bandwidth can relate to critical data, such as control data, and one or more of the communicating devices can request that the dominantly interfering device blank on one or more of the portions. The communicating devices can subsequently transmit data over the blanked portions free of the dominant interference. Additionally, the dominantly interfering device can request reciprocal blanking from the one or more communicating devices.
摘要:
In a single-carrier frequency division multiple access (SC-FDMA) system that utilizes interleaved FDMA (IFDMA) or localized FDMA, multiple transmitters may transmit their pilots using time division multiplexing (TDM), code division multiplexing (CDM), interleaved frequency division multiplexing (IFDM), or localized frequency division multiplexing (LFDM). The pilots from these transmitters are then orthogonal to one another. A receiver performs the complementary demultiplexing for the pilots sent by the transmitters. The receiver may derive a channel estimate for each transmitter using an MMSE technique or a least-squares technique. The receiver may receive overlapping data transmissions sent on the same time-frequency block by the multiple transmitters and may perform receiver spatial processing with spatial filter matrices to separate these data transmissions. The receiver may derive the spatial filter matrices based on the channel estimates for the transmitters and using zero-forcing, MMSE, or maximal ratio combining technique.
摘要:
Techniques for efficiently designing random hopping patterns in a communications system are disclosed. The disclosed embodiments provide for methods and systems for generating random hopping patterns, updating the patterns frequently, generating different patterns for different cells/sectors, and generating patterns of nearby sub-carriers for block hopping.
摘要:
A method and apparatus for generating a permutation for forward link hopping is provided, comprising initializing permutation constants, determining a value for p such that i is less than 2p wherein i is a first counter, initializing a second counter j to ‘0’, setting x to i+1 wherein x is index of elements of an array A, clocking a Pseudo-noise (PN) register n times to generate a pseudorandom number, setting x to p Least Significant Bits (LSB) of the pseudorandom number, incrementing j by 1, determining if x is greater than i, setting x equal to x−i, if x is greater than i, swapping the ith and xth element in the array A, decrementing counter i by 1, and mapping a set of hop-ports to a set of sub-carriers based upon the generated hop-permutation.
摘要:
A pruned bit-reversal interleaver supports different packet sizes and variable code rates and provides good spreading and puncturing properties. To interleave data, a packet of input data of a first size is received. The packet is extended to a second size that is a power of two, e.g., by appending padding or properly generating write addresses. The extended packet is interleaved in accordance with a bit-reversal interleaver of the second size, which reorders the bits in the extended packet based on their indices. A packet of interleaved data is formed by pruning the output of the bit-reversal interleaver, e.g., by removing the padding or properly generating read addresses. The pruned bit-reversal interleaver may be used in combination with various types of FEC codes such as a Turbo code, a convolutional code, or a low density parity check (LDPC) code.