摘要:
The embodiments utilize OFDM symbols to communicate network IDs. The IDs are encoded into symbols utilizing the network IDs as seeds to scramble respective pilots that are then transmitted by utilizing the symbols. The pilots can be structured into a single OFDM symbol and/or multiple OFDM symbols. The single symbol structure for transmitting the network IDs is independent of the number of network ID bits and minimizes frequency offset and Doppler effects. The multiple symbol structure allows a much coarser timing accuracy to be employed at the expense of transmitting additional symbols. Several embodiments employ a search function to find possible network ID candidates from a transmitted symbol and a selection function to find an optimum candidate from a network ID candidate list.
摘要:
Systems and methods are provided for channel estimation and timing synchronization in a wireless network. In an embodiment, a method is provided for time synchronization at a wireless receiver. The method includes decoding at least one TDM pilot symbol located at a transition between wide and local waveforms and processing the TDM pilot symbol to perform time synchronization for a wireless receiver. Methods for channel estimation at a wireless receiver are also provided. This includes decoding at least one TDM pilot symbol and receiving the TDM pilot symbol from an OFDM broadcast to facilitate channel estimation for a wireless receiver.
摘要:
Systems and methods are provided for the transmission of waveforms to aid channel estimation, timing synchronization, and AGC bootstrapping in a wireless network. The method includes inserting at least one TDM pilot symbol located at a transition between wide area and local area waveforms to facilitate decoding of the transmission block.
摘要:
Systems and methods are provided for processing forward link only (FLO) signals. A device receives a FLO signal, processes a TDM pilot comprising a TDM Pilot 1, a TDM Pilot 2, a WIC, a LIC, a Transition Pilot Channel, and a Positioning Pilot, from the FLO signal, processes an overhead information symbol (OIS) comprising a wide-area OIS and a local-area OIS, from the FLO signal, processes an FDM pilot comprising a wide-area FDM pilot and a local-area FDM pilot, from the FLO signal; and processes data comprising wide-area data and local-area data, from the FLO signal.
摘要:
A transmitter or receiver device includes a processing system configured to have one or more pilot interlace vectors and one or more distance vectors. The processing system is further configured to generate a first slot interlace for a first slot based on the one or more pilot interlace vectors, and is further configured to generate a second slot interlace for a second slot based on the first slot interlace and the one or more distance vectors. Additional slot interlaces for all other slots may also be generated based on the first slot interlace and the one or more distance vectors.
摘要:
Apparatus and methods for use in a wireless communication system are disclosed for determining a timing position for channel activity in order to resolve timing ambiguity. A disclosed apparatus includes a processor that determines when channel activity occurs in at least one of an early or a late arrival position in a communication channel estimate and unwraps the channel activity in either the early arrival position or the late arrival position to a corresponding late or early arrival unwrapped channel activity position in the wireless channel estimate. The processor correlates symbol data in the communication signal corresponding to both the channel activity and the unwrapped channel activity to symbol data of the main channel activity. The processor determines whether a correct timing position of the channel activity is one of the early or late arrival positions based on the correlations, thus resolving timing ambiguity. Complementary methods are also disclosed.
摘要:
Systems and methods are provided for determining and applying timing corrections in a digital communications system. In an aspect, a timing correction method is provided for a multi-carrier system. This includes aligning two or more symbols with respect to each other from a symbol subset in order to account for timing differences between the symbols. The symbol alignment is first carried out to generate channel estimates for data demodulation. The channel estimates, thus generated, along with the timing alignment information are in turn used for determining timing corrections to be applied to future symbols.
摘要:
A system and method are provided for correcting direct current (dc) offset in a wireless communications receiver. The method disconnects the mixer signal input from a received communication signal in an initialization state. An analog signal is accepted from the mixer output and converted into digital signal. A fine correction value is generated and subtracted from the digital signal. Thus, the digital signal amplitude in minimized in response to the initial fine correction value. In a communication state, the communication signals are received at the mixer signal input. The fine correction value is subtracted from a converted digital communication signal, so that the digital communication signal is supplied with a fine corrected dc offset. The method may also generate a coarse correction value to adjust mixer current in the initialization state, and a tracking correction value in the communication state.
摘要:
Pilot transmission and channel estimation techniques for an OFDM system with excess delay spread are described. To mitigate the deleterious effects of excess delay spread, time filtering is utilized. Time filtering is utilized to combat excess delay spread effects in channel estimation. The time filtering is performed in the presence of staggered pilots and helps in improving the channel estimate in the presence of excess delay spread.
摘要:
A method of generating a parity check matrix for iterative decoding of a linear block code includes: determining a set of parity check vectors for the linear block code; ordering according to Hamming weight non-zero parity check vectors of the set; selecting a criterion for generating the parity check matrix; and building the parity check matrix by incrementally selecting according to the criterion a parity check vector for each consecutive row of the parity check matrix, wherein the parity check vector is selected from the ordered non-zero parity check vectors remaining in the set.