Abstract: A physical random access channel (PRACH) waveform design to satisfy the requirements on the occupied channel bandwidth in eLAA wireless communications network is provided. In one alternative, PRACH comprises multiple segments in the time/frequency domain in one subframe. In another alternative, PRACH comprises multiple segments in the time/frequency domain across two or more subframes by using inter-subframe hopping. In one advantageous aspect, PDCCH triggers the dynamic allocation of the PRACH resource to facilitate the listen-before-talk (LBT) channel access procedure in unlicensed carriers. The aperiodic and dynamic allocation of PRACH resource improves efficiency and PRACH success rate.

Abstract: A flexible and efficient physical downlink control channel (PDCCH) signaling scheme that schedules physical uplink shared channel (PUSCH) transmission over multiple subframes with Hybrid Automatic Retransmission (HARQ) support is proposed. The PDCCH has a downlink control information (DCI) format that schedules PUSCH transmission over multiple subframes. The PUSCH transmission is associated with multiple HARQ processes with non-consecutive HARQ process IDs. Furthermore, the DCI format uses joint signaling to combine HARQ process indexes, new data indication (NDI), and redundancy version (RV) to reduce signaling overhead.

Abstract: Methods and apparatus are provided for control overhead reduction. The UE configures one or more short transmission time interval regions over a normal TTI region shared by the UE and one or more other, each UE includes a self-contained control information sPDCCH occupying a control information region. The UE detects a cover signal, which indicates one or more resource elements in the sPDCCH control-information region that can be used for data transmission. The UE obtains data transmission from the REs in the SPDCCH control information region based on the detected cover signal. In one embodiment, the cover signal is a dedicated signal. In another embodiment, the cover signal is a common signal. In yet another embodiment, the cover signal is encoded in a downlink control information (DCI) intended for the UE. In one embodiment, the cover signal indicates one or more CCE REs to be excluded for data transmission.

Abstract: Apparatus and methods are provided for low latency an ultra-low latency (ULL) communications. In novel aspect, short TTIs are configured for low latency communications. The UE configures one or more downlink short transmission time interval (sTTI) regions over a normal TTI region, decodes one or more low latency control channels, which indicates one or more sTTI regions for one or more UEs, and obtains one or more sTTI regions for the UE based on the decoded low latency control channels. In one embodiment, the location short TTI control channels is determined by detecting a short TTI control message at a beginning of a TTI and obtaining a duration of the short TTI in the detected short TTI control message. In one embodiment, the UE obtains one or more uplink resources, power control and CSI configurations based on corresponding downlink short TTI transmissions according to a mapping rule.

Abstract: Methods and apparatus are provided for transmission preemption and its indication. In one novel aspect, the UE receives a downlink resource assignment and determines whether an ultra-low latency (ULL) alert signal exists, wherein the ULL alert signal indicates a set of soft bits are overridden. The UE discards the set of soft bits from the overridden resources upon determining the ULL alert signal exists. In one embodiment, the ULL alert signal resides in the assignment subframe, and the overridden soft bits are in the assignment subframe. The alert timing for the ULL alert signal is preconfigured. In another embodiment, the ULL alert signal resides in a subframe that is right after the assignment subframe. The alert signal is enabled through an enabling of an enhanced mobile broadband and ULL service. The alter signal indicates a superset of the overridden soft bits or part of the overridden soft bits.

Abstract: A method of physical uplink control channel (PUCCH) resource allocation to increase multiplexing capacity in enhanced licensed assisted access (eLAA) is proposed. New design of Physical Uplink Control Channel (PUCCH) is proposed. Across frequency domain of the channel bandwidth, multiple resource block repetitions are allocated for different UEs for uplink PUCCH transmission to satisfy the occupied channel bandwidth requirement for unlicensed carrier access. In addition, the resource elements of a single PUCCH resource block are partially spread into different repetitions to increase multiplexing capacity and to resource peak to average power ratio (PAPR).

Abstract: A method of uplink transmission to reduce peak-to-average power ratio (PAPR) in enhanced licensed assisted access (eLAA) is proposed. New design of Physical Uplink Control Channel (PUCCH) and Physical Uplink Shared Channel (PUSCH) is proposed. Across frequency domain of the channel bandwidth, multiple resource interlaces are allocated for different UEs for uplink PUCCH/PUSCH transmission to satisfy the occupied channel bandwidth requirement for unlicensed carrier access. In addition, uplink transmission with co-phasing terms are applied to reduce PAPR of the resulted waveform.

Abstract: A method of dynamic spectrum sharing mechanism called listen-before-talk (LBT) is proposed for uplink transmission in Licensed Assisted Access (LAA). A maximum channel occupancy time (MCOT) including downlink (DL) transmission from one eNB and uplink (UL) transmission to the same eNB is introduced. A transmission sequence is defined as a number of subframes including possible partial subframes for DL and/or UL within a MCOT. The transmission in the first subframe among the transmission sequence is conducted after a Category 4 LBT. The transmission sequence within the MCOT can be initiated by either a DL transmission or an UL transmission. After the first subframe in a transmission sequence, LBT for another transmission is a fast DL LBT and/or fast UL LBT. Further, a Category 4 LBT can be converted to a short LBT (e.g., one shot CCA) for more efficient channel access.

Abstract: A method of channel access procedure and QoS provisioning is proposed. When more than one user equipments (UEs) contend uplink transmission for a given time slot in an unlicensed band, uplink listen-before-talk (LBT) scheme should perform in a proper way to reflect service prioritization. The base station first determines the Channel Access Priority (CAP) for uplink LBT, and then signals such CAP to the UE via PDCCH. Upon receiving the CAP, the UE performs LBT procedure with corresponding CAP before uplink transmission. For example, the CAP can be determined based on QoS class identifier (QCI) of the radio bearer or based on the MAC layer logical channel prioritization (LCP).

Abstract: Methods and apparatus are provided for multiplexing DRS within a transmission burst for opportunistic spectrum access. In one novel aspect, DRS is not transmitted in a fractional subframe within a TXOP. In one embodiment, if the starting fractional subframe, which contains initial signal, occurs in a configured DMTC, DRS is transmitted in the first subframe next to the starting fractional subframe. In another embodiment, if DMTC starts from a complete subframe within a TXOP, DRS is transmitted in the first candidate position within a DMTC. In another novel aspect, in the DRS subframe, PDSCH is allocated in the PRBs outside the central PRBs (six or twenty-five PRBs). In one embodiment, the reservation signal can be used to satisfy the requirement of occupied bandwidth and continuity transmission. In another embodiment, the free REs in central PRBs carry the system information when required on the unlicensed band.

Abstract: A method of distributed control achieving fair radio resource access is proposed. The parameters used in a listen-before-talk (LBT) channel access procedure that are used to control how aggressively a node contends for channel access can be called as “Channel Access Transmission Parameters” or CAT parameters. The proposed method uses randomized CAT parameters for each traffic type, and then obtains prioritized access for some nodes at any given time and fair access averaged over a period of time. More specifically, a transmitting node can use more than one set of CAT parameters even for the same traffic type instead of conventional only use one set of CAT parameters for one traffic type. The transmitting node can use a set of CAT parameters according to a fixed schedule, a random rule, or a pseudo-random rule.

Abstract: A method of determining and configuring a maximal clear channel assessment (CCA) duration based on channel loading information for frame-based equipment (FBE) listen before talk (LBT) channel access mechanism is proposed. The CCA period is a random CCA duration generated out of the maximal CCA duration, which is configurable and is carried in the radio resource control (RRC) signaling or the beacon signal of LAA. To solve the collision problem in synchronous network and the unfairness problem in asynchronous network, the maximal duration of CCA should be adaptive based on the experienced channel occupancy status and/or the experienced synchronization difference within the network. First, the maximal duration of CCA should be adjusted according to the channel loading. Second, the maximal duration of CCA should be larger than the timing difference between eNBs or between UEs.

Abstract: A method of determining and adapting a contention window size (CWS) based on channel loading for load-based equipment (LBE) listen before talk (LBT) channel access mechanism is proposed. The historic observations obtained from carrier sensing can reflect the state of channel loading, which is then used to adapt the maximal contention window size. A wireless device collects historical channel loading information including the number of idle slots and the number of busy slots. The wireless device uses the historical information to estimate the total number of active devices M in the wireless network and the channel-loading factor. The wireless device then computes the thresholds using the long-term value of M and then adapts the value of the CWS based on the channel-loading factor and the thresholds.

Abstract: Periodic Radio Resource Management (RRM) reporting from user equipments (UEs) is beneficial for a network to efficiently select a carrier with a cleaner channel to serve the UEs. To enable periodic RRM reporting from UEs, periodic beacon signal transmission for UE measurements is necessary. However, in a shared spectrum, precise periodic transmission cannot be guaranteed due to channel contention. A method of transmission with periodic time windows for beacon signal transmission is proposed to resolve potential issues. Under the proposed solution, beacon signal can be transmitted in a certain periodic fashion without frequent physical layer signaling. Furthermore, periodic beacon signal transmission for measurements can be kept with low transmission failure rate due to channel contention.

Abstract: Methods and apparatus are provided for improved Licensed Assisted Access (LAA) networks. A LAA subframe is received via an unlicensed frequency band. Control information is communicated via predetermined symbol locations within the LAA subframe. An indication of a first and a second symbol locations is received. A LAA subframe is then received. It is determined if control information is present at the first or second symbol locations within the received LAA subframe. Demodulation parameters based on the control information are determined. The LAA subframe is demodulated using the demodulation parameters. An indication of a transmission duration is communicated to a UE. The transmission duration is determined based on the LAA subframe. A type of subframe is determined based on transmission duration. Automatic Gain Control (AGC) protection is provided in a LAA subframe. The AGC protection LLA subframe does not communicate control information in a symbol adjacent to a reservation signal.