摘要:
The present invention relates to a multi-stream communication system comprising a transmitting node provided with a polyphase antenna and a receiving node provided with an antenna arrangement configured to receive multiple data streams. The polyphase antenna has at least one group of multiple antenna elements, each group having N antenna elements. The transmitting node is also provided with at least one radio chain and a switch for each radio chain arranged to cyclically connect each radio chain to the antenna elements in one of the groups. The switch is configured to operate with a switching frequency fsw. The transmitting node is further configured to transmit M weighted symbols of an uncorrelated signal from each antenna element in each group, the M weighted symbols being less than or equal to N, and the receiving node is further configured to convert the received N data streams into each respective uncorrelated signal.
摘要:
The present invention relates to a solution for determining wireless communication cell characteristics related to wireless MIMO transmission mode and dynamically selecting suitable communication transmission mode for certain parts of the wireless communication cell. The solution uses a flatness spectrum analysis of received impulse response from a plurality of measurement points in the cell using a plurality of antennas in a wireless network access gateway, e.g. a base station.
摘要:
The present invention relates to a solution for determining wireless communication cell characteristics related to wireless MIMO transmission mode and dynamically selecting suitable communication transmission mode for certain parts of the wireless communication cell. The solution uses a flatness spectrum analysis of received impulse response from a plurality of measurement points in the cell using a plurality of antennas in a wireless network access gateway, e.g. a base station.
摘要:
The present invention relates to a multi-stream communication system comprising a transmitting node provided with a polyphase antenna and a receiving node provided with an antenna arrangement configured to receive multiple data streams. The polyphase antenna has at least one group of multiple antenna elements, each group having N antenna elements. The transmitting node is also provided with at least one radio chain and a switch for each radio chain arranged to cyclically connect each radio chain to the antenna elements in one of the groups. The switch is configured to operate with a switching frequency fsw. The transmitting node is further configured to transmit M weighted symbols of an uncorrelated signal from each antenna element in each group, the M weighted symbols being less than or equal to N, and the receiving node is further configured to convert the received N data streams into each respective uncorrelated signal.
摘要:
A method for processing signals to be transmitted in a MIMO system from a transmitter having at least two transmitting antennas to a receiver having at least two receiving antennas on a frequency selective communication channel. The method comprises estimating elements of a channel matrix H(q−1) based on time delays and complex valued coefficients associated with the communication channel to provide an estimated frequency variation function of each element of the channel matrix, and pre-coding the signals to be transmitted based on the estimated frequency variation function for each element. The invention also relates to a MIMO system; and a transmitter and a receiver for use in a MIMO system.
摘要:
A method and unit for composing or decomposing a multimedia signal according to the Musical Instrument Digital Interface (MIDI) protocol. The signal carries events of a first type, which are arranged to carry instructions regarding which predefined patches to use for playback and which predefined notes to play, and events of a second type which carry additional content. The signal is parsed to identify events of the second type and to read the additional content. Coded samples of multimedia content are loaded at an address specified in the additional content. The coded samples are then decoded to provide the samples for playback of the multimedia content. In this manner, vocal song or vocals and other audio type signals are efficiently conveyed utilizing the widely used MIDI protocol.
摘要:
A method of and a precoding device and a communication device for precoding transmit data signals in a wireless Multiple-Input Multiple-Output, MIMO, channel transmission scheme for maximizing channel capacity of the MIMO system given available amounts of transmit power. The precoding is expressed in a complex precoding matrix (W), which is calculated involving individual transmit power constraints of the multiple outputs (71, . . . , 7t) of the MIMO channel. The individual transmit power constraints are comprised of predetermined individual output transmit power amplifier (PA1, . . . , PAt) limitations.
摘要:
The present invention relates to a node (1) in a wireless communication network, where the node (1) is arranged to receive at least two signals (y1(n), y2(n)) which correspond to at least two transmitted uncorrelated signal streams (x1(n), X2(n)) which have been transmitted to the node via a channel. The channel (2) is signals represented by means of a channel matrix (H(q−1)). The node (1) comprises a controllable filter structure (3) that is arranged to diagonalize the channel matrix (H(q−1)) such that a channel matrix estimation (Ĥ(q−1)) may be obtained. The present invention also relates to a corresponding method.
摘要:
For compensating carrier frequency generation in communication equipment for radio transmission in an Orthogonal Frequency Division Multiplex, OFDM, based wireless radio communication system, in which reference signals known communication equipment are transmitted in a regular time repetitive manner, carrier frequency generation is compensated (63) by a calculated carrier frequency offset estimate. The carrier frequency offset estimate in the communication equipment is calculated from coarse (61) and fine carrier frequency offset estimates (62). The coarse carrier frequency offset estimate (61) is calculated in the frequency domain from reference symbols of a reference signal received (60) at the communication equipment and the fine carrier frequency offset estimate (62) is calculated in the time domain from reference symbols of reference signals repetitively received (60) at said communication equipment. An algorithm and an estimator module (90) for calculating a coarse carrier frequency offset are provided.
摘要:
Speech enhancement is provided in dual microphone noise reduction systems by including spectral subtraction algorithms using linear convolution, causal filtering and/or spectrum dependent exponential averaging of the spectral subtraction gain function. According to exemplary embodiments, when a far-mouth microphone is used in conjunction with a near-mouth microphone, it is possible to handle non-stationary background noise as long as the noise spectrum can continuously be estimated from a single block of input samples. The far-mouth microphone, in addition to picking up the background noise, also picks up the speaker's voice, albeit at a lower level than the near-mouth microphone. To enhance the noise estimate, a spectral subtraction stage is used to suppress the speech in the far-mouth microphone signal. To be able to enhance the noise estimate, a rough speech estimate is formed with another spectral subtraction stage from the near-mouth signal. Finally, a third spectral subtraction function is used to enhance the near-mouth signal by suppressing the background noise using the enhanced background noise estimate. A controller dynamically determines any or all of a first, second, and third subtraction factor for each of the first, second, and third spectral subtraction stages, respectively.