Patent application number | Description | Published |
20150023315 | LTE CHANNEL ACCESS OVER UNLICENSED BANDS - Methods, systems, and devices are described for wireless communications. In one method, a clear channel assessment (CCA) may be performed at a base station to determine availability of an unlicensed spectrum. A first waveform may be transmitted to a set of user equipments (UEs) over the unlicensed spectrum when available. The first waveform may indicate a first time period and a second time period during which the base station has channel access over the unlicensed spectrum. A second waveform may be received from one or more UEs responsive to the first waveform. Each second waveform may be received over the unlicensed spectrum during the first time period and may indicate that the respective UE has channel access over the unlicensed spectrum to receive data from the base station during the second time period. | 01-22-2015 |
20150043523 | TRANSMISSION AND RECEPTION OF COMMON CHANNEL IN AN UNLICENSED OR SHARED SPECTRUM - Methods, systems, and apparatuses are described for wireless communications, in which transmission of common information to two or more receivers over unlicensed spectrum may be provided. The common information may be transmitted over a number (e.g., a set) of different carrier frequencies of the unlicensed spectrum. A staggering pattern may be employed to transmit all or a part of the common information across each of the carrier frequencies in the set of carrier frequencies. The detection of the information on one of the carrier frequencies may provide information that may be used to derive the staggering pattern. The duration of the common information transmission on each of the carrier frequencies may be selected such that a clear channel assessment (CCA) to determine availability of the unlicensed spectrum is not required. | 02-12-2015 |
20150043687 | INTRA-FREQUENCY AND INTER-RAT RECEIVER - Techniques are described for wireless communications. In one example, multiple signals including at least a wireless local area network (WLAN) signal and a cellular signal may be received over a bandwidth of an unlicensed radio frequency spectrum band. Digital samples of the signals may be stored in a buffer. At least a portion of the WLAN signal may be reconstructed from the stored digital samples and removed from the stored digital samples before the contents of the buffer are converted to the frequency domain for demodulation and decoding of the cellular signal by a cellular receiver. In another example, multiple signals may be received over a bandwidth of an unlicensed radio frequency spectrum band, and it may be determined whether to apply codeword-level interference cancelation (CWIC) or symbol-level interference cancelation (SLIC) to remove an interference signal in the multiple signals. | 02-12-2015 |
20150049715 | SUBFRAME STAGGERING ACROSS COMPONENT CARRIERS IN AN UNLICENSED OR SHARED SPECTRUM - Methods, systems, and devices are described for clear channel assessments (CCAs) on multiple component carriers transmitted using an unlicensed spectrum. A set of component carriers may be identified for transmission of communications signals on the unlicensed spectrum, and a CCA one component carrier of the set may be staggered to occur at a different time than a CCA for a different component carrier of the setoff component carriers. The staggering of CCAs may allow for CCA to be performed at different times for different component carriers, thus increasing opportunities to gain channel access in the unlicensed spectrum. | 02-19-2015 |
20150055588 | CSI AND ACK REPORTING ENHANCEMENTS IN LTE/LTE-A WITH UNLICENSED SPECTRUM - Channel state information (CSI) and acknowledgement (ACK) reporting enhancements in Long Term Evolution (LTE)/LTE-Advanced (LTE-A) enabling communications over an unlicensed spectrum are disclosed. For example, ACK/NAK may include unlicensed spectrum interference information, such as WIFI interference. Additionally, in anticipation of a future downlink transmission, UEs may report WiFI interference to base stations absent a current downlink transmission. Also, CSI-RS and/or IMR resources may be staggered across subframes and/or within slots of subframes. Further, CSI reporting may include separate reports for CSI-RS resources that experience unlicensed spectrum interference and interference free CSI-RS resources. Still further, CSI reports may include a request to the base station to switch the current channel or band. Finally, inter-RAT ACK and CSI reporting may be provided on a second unlicensed spectrum band, such as a WIFI band, for a first unlicensed spectrum band, such as an LTE/LTE-A unlicensed band. | 02-26-2015 |
20150055589 | COMMON HARQ PROCESSES - A sharing of common hybrid automatic repeat request (HARQ) process space by multiple unlicensed spectrum component carriers is described. Because communication access is not guaranteed over the unlicensed spectrum, a set of component carriers in the unlicensed spectrum is assigned to share a common HARQ process space, such that uplink or downlink data will be transmitted over any one or more of the set of component carriers that clear a clear channel assessment (CCA) check. The receiver then provides a HARQ process response over the same HARQ process space using the grouped component carriers that share that common HARQ process space. Thus, any one or more of the set of component carriers sharing the common HARQ process space may both carry the transmitted data and carry the HARQ process response to the attempted data transmission. | 02-26-2015 |
20150056931 | DETECTION OF BURSTY WIFI INTERFERENCE IN LTE/LTE-A COMMUNICATIONS IN AN UNLICENSED SPECTRUM - Methods, systems, and devices are described for detection of one or more interfering signals in a particular frequency spectrum. Signal characteristics may be identified for a signal of interest in the spectrum, such as a signal that is desired to be received at a wireless communications device. Based at least in part on the characteristics, one or more interference detection opportunities may be identified, during which interfering signals in the spectrum may be detected. Interference detection opportunities may include, for example, periods when the signal of interest may be absent from the particular frequency spectrum. Transmissions in the frequency spectrum may be monitored during the interference detection opportunity to determine the presence of one or more interfering signals. | 02-26-2015 |
20150067435 | RESOURCE MAPPING TO HANDLE BURSTY INTERFERENCE - Resource mapping and coding schemes to handle bursty interference are disclosed that provide for spreading the modulated symbols for one or more transmission code words over more symbols in the time-frequency transmission stream. Certain aspects allow for the modulated symbols to be based on bits from more than one code word. Other aspects also provide for re-mapping code word transmission sequences for re-transmissions based on the number of re-transmissions requested by the receiver. Additional aspects provide for layered coding that uses a lower fixed-size constellation to encode/decode transmissions in a layered manner in order to achieve a larger-size constellation encoding. The layered encoding process allows the transmitter and receiver to use different coding rates for each coding layer. The layered encoding process also allows interference from neighboring cells to be canceled without knowledge of the actual constellation used to code the interfering neighboring signal. | 03-05-2015 |
20150085797 | LTE-U UPLINK WAVEFORM AND VARIABLE MULTI-SUBFRAME SCHEDULING - Uplink waveforms for operating long term evolution (LTE) in an unlicensed band (i.e., long term evolution-unlicensed (LTE-U) communication) are disclosed. Carrier aggregation (CA) and standalone (SA) are disclosed. LTE on the licensed channel may provide both control and data, LTE on the unlicensed channel may provide data. Managing variable transmission time interval (TTI) continuous transmission is disclosed for transmission over multiple subframes of an unlicensed carrier in LTE-U. Listen-before-talk (LBT) requirements of unlicensed carriers provide for additional channel occupancy constraints when scheduling resources for multiple UEs for variable TTI continuous uplink transmissions over multiple subframes. A joint control channel is disclosed that provides control information for all of the potentially available subframes to be scheduled for the uplink transmissions. In addition to management of the variable TTI continuous transmissions, adjustments to uplink signal parameters are also disclosed that address the constraints due to the LBT requirements of unlicensed carriers. | 03-26-2015 |