Abstract: The present invention discloses a method and an apparatus for eliminating frequency-domain interference signals, and relates to communication technologies. The method includes: multiplying a frequency-domain channel estimation value by a frequency-domain interference signal to obtain a frequency-domain received interference signal; and subtracting the frequency-domain received interference signal from the frequency-domain received signal to obtain the frequency-domain received signal free of interference. The apparatus includes a multiplying module and a subtracting module. A frequency-domain equalizer includes an interference signal obtaining module and an interference signal eliminating module. The technical solution provided herein eliminates interference signals in the frequency domain, and saves the calculation load in contrast with elimination of time-domain interference signals.

Abstract: Method and apparatus are provided for estimating Time of Arrival (“TOA”). The method includes: performing channel estimation according to a Normal Burst (“NB”) free of interference and a local training sequence and generating a channel estimate, performing TOA estimation according to the channel estimate, and adjusting a synchronization position of the current NB according to a TOA estimation result. Interference to signals is cancelled before the TOA estimation, thus overcoming energy estimate deviation arising from interference in a strongly interfering radio environment, as occurs in the prior art, and preventing the impact on the TOA estimation. The disclosed methods and apparatus provide for more accurate energy estimates in a strongly interfering radio environment. The technical solution under the present invention does not require adjustment of the method of adjusting the search window.

Abstract: The present invention discloses a method and an apparatus for searching for modes and frequencies. The method includes: obtaining signal energy of all frequency grids within a frequency range; obtaining energy of each mode on a smallest bandwidth according to the signal energy of the grids; sorting the energy on the smallest bandwidths of all modes; and accessing a specified number of frequencies and modes of the highest energy in the sorting result. With the present invention, energy on the smallest bandwidths of all modes at a frequency band is obtained and sorted and then an access mode is determined according to the sorting result. Thus the access mode to use for a specified frequency can be quickly determined so as to improve the access success rate of a terminal in the subsequent access process.

Abstract: A method and device for estimating a Gaussian white noise power in a channel and a receiver are provided. The method includes performing a multi-path search on a received signal to find out paths of the signal; performing a noise estimation on one of the paths to acquire a total noise power of the path; performing an inter-path interference noise estimation on N paths spaced apart from the path by an integral number of chips to obtain an inter-path interference noise power of a single path of the signal, where N is an integer greater than or equal to 1; and subtracting the inter-path interference noise power from the total noise power to obtain the Gaussian white noise power. Through the technical solution of the disclosure, the Gaussian white noise power in a channel is obtained with a higher accuracy, so that the performance of equalization is enhanced.

Abstract: A cascade encoding method and apparatus are applied to a handheld television system or other fields. The method includes the following: A. Reed-Solomon (RS) encoding is performed on inputted Medium Access Control (MAC) packets, and coded MAC packets are outputted; and B. Low density parity check code (LDPC) encoding is performed on the coded MAC packets, and LDPC encoding blocks are outputted. The apparatus includes an RS coder and an LDPC coder. The RS encoding and LDPC encoding are cascaded to encode an inputted code flow, so as to reduce an error rate. Meanwhile, bytes in one RS encoding data block are dispersed into different LDPC blocks to be encoded through byte interleaving, thereby sufficiently utilizing error code characteristics of the RS encoding and the LDPC encoding for decoding, and improving error correction capability of a system.

Abstract: Embodiments of the present invention provide a method and a system for removing a Radio Frequency (RF) Direct Current (DC) offset in a signal. The method includes: subtracting a canceling DC from a signal carrying an RF DC offset and generating an RF DC offset residual; outputting the signal when the RF DC offset residual in the signal is zero; adjusting the canceling DC according to the RF DC offset residual in the signal if the RF DC offset residual is not zero. The system includes a receiver, an RF DC offset canceling unit, a determining unit, a canceling DC adjusting unit, and an output unit. With embodiments of the present invention, the RF DC offset in the signal may be effectively removed.

Abstract: A method of frame synchronization includes: inserting synchronous pilots including odd synchronous pilots and even synchronous pilots in a frame; transmitting first signals on the odd synchronous pilots, and transmitting second signals of inverse values of the first signals transmitted on the odd synchronous pilots on the even synchronous pilots; synchronizing the frame according to the odd synchronous pilots and the even synchronous pilots. With the method provided by embodiments of the present invention, complexity of the frame synchronization may be decreased and delay of the frame synchronization may be reduced.

Abstract: A method and system for implementing synchronization between a receiving end and a source end of broadcast television service. The method includes: determining, at a transmitting station, time difference information between the source end and the transmitting station; and transmitting, by the transmitting station, time information of the transmitting station and the time difference information to the receiving end; implementing, by the receiving end, synchronization between the receiving end and the source end according to the time difference information and the time information of the transmitting station. With the method, synchronization between the source end and the receiving end in a broadcast television service network may be realized so that the receiving end may learn the accurate initial time information for receiving program streams transmitted from the program source. With the method, energy waste due to in-advance turn-on of receiving end device for receiving a program may be avoided.

Abstract: A method for distributing encryption keys in WLAN that combines a key distribution process with an authentication process of mobile hosts and utilizes an authentication server or a wireless gateway to manage key distribution so that mobile hosts can roam in a scope larger than the coverage area of the key management server. Because the key distribution does not transmit the key, which is not encrypted via the air interface, the method ensures the key is safe. In addition, the method can be used under different WLAN protocols. Because the AP does not need to manage user information, the method simplifies AP structure, and thus lowers the cost.