12 results about "Subcarrier" patented technology

Adaptive modulation techniques for multi-antenna transmissions with partial channel knowledge are described. Initially, a transmitter is described that includes a two-dimensional beamformer where coded data streams are power loaded and transmitted along two orthogonal basis beams. The transmitter optimally adjusts the basis beams, the power allocation between two beams, and the signal constellation. A partial CSI model for orthogonal frequency division multiplexed (OFDM) transmissions over multi-input multi-output (MIMO) frequency selective fading channels is then described. In particular, an adaptive MIMO-OFDM transmitter is described in which the adaptive two-dimensional coder-beamformer is applied on each OFDM subcarrier, along with an adaptive power and bit loading scheme across the OFDM subcarriers.

The invention provides an information transmission method in a subcarrier time slot (TS) 0, which comprises the following step of: configuring one or any combination of downlink channels related to a DL DPCH and HSDPA (including an HS-SCCH and an HS-PDSCH), downlink channels related to HSUPA (including an E-AGCH and an E-HICH) and an FPACH in the subcarrier TS0 so as to transmit information between a NodeB and user equipment (UE) on the configured corresponding channels. By the method, the channel is configured in the subcarrier TS0 and corresponding data transmission is performed on the configured channel, so that the utilization rate of a frequency spectrum is greatly improved.

CSIT error considerate delay-sensitive user access systems are provided in a multi-user OFDMA environment comprises a user delay sensitivity tracking component, a CSIT estimating component, a system queue state tracking component and a cross layer scheduling component. The techniques assume heterogeneous users with respect to delay and assume that CSIT information includes error, and optimally allocates broadcast resources, e.g., power, subcarriers and data rate, based on such assumptions.

The invention discloses a signal configuration method, an information processing method, and devices. The signal configuration method comprises the following steps: selecting a plurality of synchronous windows contained in a preset period of time to carry a synchronous signal; configuring a broadcast channel according to the preset constraint relationship between the synchronous signal and the broadcast channel; and sending a configured signal by means of periodic trigger or non-periodic trigger, wherein the configured signal includes at least one of the synchronous signal and the broadcast channel, and a complete process of signal transmission is completed in the preset period of time. Each synchronous window includes a plurality of successive symbols. The synchronous signal is carried by a plurality of subcarriers of each symbol. The transmission process of the synchronous signal is completed in the preset period of time.

A receiving station apparatus controls a number of null carriers included in a transmission signal transmitted by a transmitting station apparatus in a communication system adopting a multicarrier modulation system to suppress inter-carrier interference by using the null carrier. For example, a reception-quality measuring unit measures a reception quality of a subcarrier group forming the transmission signal, and a number-of-null carriers determining unit determines the number of null carriers included in a next transmission signal based on the reception quality.

The invention relates to a blind estimation method for the signal to noise ratio of an OFDM system, and belongs to the technical field of wireless communication. Data subcarrier mean power and virtual carrier mean power are obtained on the basis of preambles of signal frames of the OFDM system, and further the signal to noise ratio is determined. Thus, the communication efficiency is higher compared with a pilot-aided estimation method for the signal to noise ratio in the prior art; the estimation precision is higher compared with a signal to noise ratio estimation method in which virtual carriers are used, and the blind estimation method of the invention is low in complexity, easy to realize and low in realization cost.

When a signal transmitted by orthogonal frequency division multiplexing is received, the received signal having been converted to a desired frequency is transformed by Fourier transformation (1); a sub-carrier frequency is divided into an even-number multiple sub-carrier component (D2) and an odd-number multiple sub-carrier component (D4) of a sub-carrier interval; the position of an impulse noise component is determined based on the size of electric power of front halves (D3p, D5p) and rear halves (D3q, D5q) of signals that have undergone reverse Fourier transformation (3, 5); and signals little affected by impulse noise are used to reconfigure a time domain signal (D) of even-numbered sub-carrier components and a time domain signal (D) of odd-numbered sub-carrier components, after which the signals are added (10), transformed again by Fourier transformation (11) and demodulated (12). The effects of impulse noise can be reduced to improve reception performance.

The invention relates to an anti-interference transmission method and device, computer equipment and a storage medium, belonging to the technical field of data transmission. The method includes the following steps: determining an interfered subcarrier within a transmission bandwidth; selecting a remapping subcarrier from the two sides of the transmission bandwidth in an out-of-band mode accordingto the interfered subcarrier; combining the selected remapping subcarrier and subcarriers that are not interfered within the transmission bandwidth to obtain an available subcarrier set; and performing data transmission through the available subcarrier set. According to the above technical scheme, the problem that an interference source in an OFDM system cannot be avoided in a targeted manner canbe solved, the influence of the interference can be eliminated in a targeted manner, and the efficiency and accuracy of the transmission of the interfered data can be improved.

Various methods and systems are provided for edge windowing of orthogonal frequency division multiplexing (OFDM) systems. In one example, among others, a method includes obtaining an edge windowing portion by reducing a cyclic prefix size for a quantity of edge subcarriers in an OFDM symbol and reducing side lobes by applying a windowing function to the edge subcarriers. In another example, a device includes a separator capable of dividing subcarriers of an OFDM symbol into first and second subcarrier groups, a first CP adder capable of obtaining a windowing portion by adjusting a cyclic prefix size of the first subcarrier group, and a first windower capable of reducing side lobes by applying a windowing function to the first subcarrier group. In another example, a method includes determining a RMS delay spread of a mobile station and scheduling a subcarrier based at least in part upon the RMS delay spread.

A method for co-channel interference suppression in Orthogonal Frequency Division Multiplexing (OFDM) systems with multiple receiving antennas is provided, wherein the co-channel interference (CCI) in different directions is suppressed by the spatial technique provided by the antenna arrays, and the interference to a desired carrier caused by other sub-carriers is also taken into consideration, that is, the interference of other sub-carriers is cancelled by means of a multistage interference cancellation, thereby the performance for interference suppression is improved.

A wireless network includes a plurality of access points with at least pairwise overlapping wireless coverage, each of the access points comprising an OFDMA modulation system and a channel scheduler coupled to the OFDMA modulation system which is configured to set up a number of virtual wireless interfaces of the access point, each virtual wireless interface being associated with a dedicated set of subcarriers within the OFDMA spectrum. At least one first of the virtual wireless interfaces is configured to host all communication links between the access point and local mobile clients to the access point. A least one second of the virtual wireless interfaces is configured to host communication links between the access point and one of the neighbouring access points.

The invention provides an anti-large frequency offset solution method based on a 5G random access preamble long sequence, and the method employs the cyclic prefix of a random preamble to calculate and correct the decimal frequency offset, and solves the influence of a secondary peak generated by the decimal frequency offset on the detection performance of a preamble sequence. After fast Fourier transform, five paths of frequency domain data with different integer frequency offsets are constructed in a mode of extracting effective subcarrier frequency domain data from the subcarrier frequency domain data; then, matching is carried out by adopting different root sequences according to the characteristic of preamble cyclic shift, and the maximum value is judged through search window shift, so the processing time of sequence detection and the hardware resource consumption are reduced; and the influence of integer frequency offset on random access caused by inaccurate frequency offset calculation and application scenarios under the condition of low signal-to-noise ratio is solved by utilizing a five-path parallel matching scheme.