Abstract: Various optical detector pixel embodiments are described. One optical detector pixel includes a photodiode having a first end opposite a second end, a set of lateral walls joining the first end and the second end, and a depth parallel to the set of lateral walls. A lens is positioned to direct light toward the first end of the photodiode. A set of one or more optical scattering structures laterally extends at least partially into an illumination area defined by the lens and has a set of sidewalls extending away from the first end. The set of sidewalls includes a pair of sidewalls forming an included angle. The included angle extends perpendicular to the depth of the photodiode. The pair of sidewalls abut a portion of the photodiode.

Abstract: Systems, methods, and instrumentalities are disclosed for narrowband (NB) LTE operation. A WTRU may receive a first downlink data transmission, for example, via a physical downlink shared channel (PDSCH). The WTRU may determine to send a hybrid automatic repeat request (HARQ) acknowledgment (ACK) in response to receipt of the first downlink data transmission. The WTRU may transmit a first uplink reference signal. The WTRU may indicate the HARQ-ACK using a first cyclic shift index that is applied to the first uplink reference signal. The WTRU may determine to send a HARQ negative ACK (HARQ-NACK), for example, on a condition that a second downlink data transmission is not correctly received. The WTRU may send a second uplink reference signal. The WTRU may indicate the HARQ-NACK using a second cyclic shift that is applied to the second uplink reference signal.

Abstract: Systems, methods, and instrumentalities are disclosed for interleaving coded bits. A wireless transmit/receive unit (WTRU) may generate a plurality of polar encoded bits using polar encoding. The WTRU may divide the plurality of polar encoded bits into sub-blocks of equal size in a sequential manner. The WTRU may apply sub-block wise interleaving to the sub-blocks using an interleaver pattern. The sub-blocks associated with a subset of the sub-blocks may be interleaved, and sub-blocks associated with another subset of the sub-blocks may not be interleaved. The sub-block wise interleaving may include applying interleaving across the sub-blocks without interleaving bits associated with each of the sub-blocks. The WTRU may concatenate bits from each of the interleaved sub-blocks to generate interleaved bits, and store the interleaved bits associated with the interleaved sub-blocks in a circular buffer. The WTRU may select a plurality of bits for transmission from the interleaved bits.

Abstract: A method performed by a WTRU may comprise generating a polar factor graph and pruning the polar factor graph to generate a pruned factor graph. The pruned factor graph may include input variable nodes, check nodes and output variable nodes. The method may further comprise the initializing input variable nodes. For each of a plurality of encoding levels of the pruned factor graph, values from the input variable nodes may be transferred to the check nodes. Operations, for example, XOR) additions, may be performed on the values of the check nodes. Check nodes having a single connection to another node not used in a previous transfer may be identified. Values from the identified check nodes may be transferred to the input variable nodes. Binary values from the input variable nodes may be transferred to the output variable nodes for transmission to a receiver.

Abstract: Systems, methods, and instrumentalities are disclosed for interleaving coded bits. A wireless transmit/receive unit (WTRU) may generate a plurality of polar encoded bits using polar encoding. The WTRU may divide the plurality of polar encoded bits into sub-blocks of equal size in a sequential manner. The WTRU may apply sub-block wise interleaving to the sub-blocks using an interleaver pattern. The sub-blocks associated with a subset of the sub-blocks may be interleaved, and sub-blocks associated with another subset of the sub-blocks may not be interleaved. The sub-block wise interleaving may include applying interleaving across the sub-blocks without interleaving bits associated with each of the sub-blocks. The WTRU may concatenate bits from each of the interleaved sub-blocks to generate interleaved bits, and store the interleaved bits associated with the interleaved sub-blocks in a circular buffer. The WTRU may select a plurality of bits for transmission from the interleaved bits.

Abstract: Methods and apparatuses for relaxed polar coding, including cyclic redundancy check (CRC) aided encoding and belief propagation (BP) decoding for relaxed polar codes in wireless communications, are provided. For example, a method comprises determining: 1) a first set of encoding nodes used for creating CRC bits, 2) a first set of polarization branches, each associated with a respective encoding node of the first set of encoding nodes, and 3) a second set of polarization branches, each of the second set of polarization branches is at least one level higher than a respective polarization branch of the first set of polarization branches. The method also comprises performing polar encoding operation(s) for the second set of polarization branches including relaxation, generating a second set of encoding nodes based on the performed polar encoding operation(s) for the second set of polarization branches, and transmitting polar code bits using the generated second set of encoding nodes.

Abstract: A polar code may be initially divided into multiple polar component codes where the features of these component codes, such as the number of component codes and the size of the component codes, are determined based on parameters such as the number of available timing units within a transmission interval, interleaving depth, and decoder capability. For each selected component code, the order of code bit generation and their indexes may be determined. The determined indexes may be assigned into different, unique groups according to the order of code bit generation. An interleaving operation may be configured and then executed according to the determined index grouping. In the transmission phase, the code bits may be transmitted based on the identified order of the bit generation in the component polar codes, such as the determined index grouping.

Abstract: In certain representative embodiments, methods, apparatus and systems are provided for the selection of component codes for input as cyclic redundancy check (CRC) bits during polar encoding. The component polar codes and particular encoded bits in these component codes that will be used in CRC calculation can be selected. A CRC calculation may be performed based on the component codes and the selected encoded bits. The calculated CRC bits may be appended to a header part of the input bits of the polar encoder. Polar encoding may then be performed using the input bits which include the calculated CRC bits appended thereto. For example, the polar encoding may skip encoding levels used in accordance with the component code selection. The polar encoding may have improved complexity and/or latency characteristics. In certain representative embodiments, methods, apparatus and systems are provided for polar decoding having improved complexity and/or latency characteristics.

Abstract: Systems, methods, and instrumentalities are disclosed for narrowband (NB) LTE operation. A WTRU may receive a first downlink data transmission, for example, via a physical downlink shared channel (PDSCH). The WTRU may determine to send a hybrid automatic repeat request (HARQ) acknowledgment (ACK) in response to receipt of the first downlink data transmission. The WTRU may transmit a first uplink reference signal. The WTRU may indicate the HARQ-ACK using a first cyclic shift index that is applied to the first uplink reference signal. The WTRU may determine to send a HARQ negative ACK (HARQ-NACK), for example, on a condition that a second downlink data transmission is not correctly received. The WTRU may send a second uplink reference signal. The WTRU may indicate the HARQ-NACK using a second cyclic shift that is applied to the second uplink reference signal.

Abstract: Systems, methods, and instrumentalities are disclosed for narrowband (NB) LTE operation. A WTRU may receive a first downlink data transmission, for example, via a physical downlink shared channel (PDSCH). The WTRU may determine to send a hybrid automatic repeat request (HARQ) acknowledgment (ACK) in response to receipt of the first downlink data transmission. The WTRU may transmit a first uplink reference signal. The WTRU may indicate the HARQ-ACK using a first cyclic shift index that is applied to the first uplink reference signal. The WTRU may determine to send a HARQ negative ACK (HARQ-NACK), for example, on a condition that a second downlink data transmission is not correctly received. The WTRU may send a second uplink reference signal. The WTRU may indicate the HARQ-NACK using a second cyclic shift that is applied to the second uplink reference signal.

Abstract: A polar code may be initially divided into multiple polar component codes where the features of these component codes, such as the number of component codes and the size of the component codes, are determined based on parameters such as the number of available timing units within a transmission interval, interleaving depth, and decoder capability. For each selected component code, the order of code bit generation and their indexes may be determined. The determined indexes may be assigned into different, unique groups according to the order of code bit generation. An interleaving operation may be configured and then executed according to the determined index grouping. In the transmission phase, the code bits may be transmitted based on the identified order of the bit generation in the component polar codes, such as the determined index grouping.

Abstract: Systems, methods, and instrumentalities are disclosed for interleaving coded bits. A wireless transmit/receive unit (WTRU) may generate a plurality of polar encoded bits using polar encoding. The WTRU may divide the plurality of polar encoded bits into sub-blocks of equal size in a sequential manner. The WTRU may apply sub-block wise interleaving to the sub-blocks using an interleaver pattern. The sub-blocks associated with a subset of the sub-blocks may be interleaved, and sub-blocks associated with another subset of the sub-blocks may not be interleaved. The sub-block wise interleaving may include applying interleaving across the sub-blocks without interleaving bits associated with each of the sub-blocks. The WTRU may concatenate bits from each of the interleaved sub-blocks to generate interleaved bits, and store the interleaved bits associated with the interleaved sub-blocks in a circular buffer. The WTRU may select a plurality of bits for transmission from the interleaved bits.

Abstract: Systems, methods, and instrumentalities are described herein that may be used for reduced complexity polar encoding and decoding. There may be a set of encoding nodes to be used for polar encoding. An encoding node may be associated with a bit index and/or a relaxation level. A relaxation attribute may be selected for the encoding node. A relaxation group may be determined based on the relaxation attributes. The relaxation group may include two encoding nodes associated with consecutive bit indexes, an initial relaxation level, and the first relaxation attribute. A final relaxation level may be determined. Relaxation may be performed on the encoding nodes in the relaxation group. For example, an XOR operation between the encoding nodes may be omitted. Relaxation may be performed on the encoding nodes associated with each relaxation level up to the final relaxation level.

Abstract: Systems, methods, and instrumentalities are disclosed for interleaving coded bits. A wireless transmit/receive unit (WTRU) may generate a plurality of polar encoded bits using polar encoding. The WTRU may divide the plurality of polar encoded bits into sub-blocks of equal size in a sequential manner. The WTRU may apply sub-block wise interleaving to the sub-blocks using an interleaver pattern. The sub-blocks associated with a subset of the sub-blocks may be interleaved, and sub-blocks associated with another subset of the sub-blocks may not be interleaved. The sub-block wise interleaving may include applying interleaving across the sub-blocks without interleaving bits associated with each of the sub-blocks. The WTRU may concatenate bits from each of the interleaved sub-blocks to generate interleaved bits, and store the interleaved bits associated with the interleaved sub-blocks in a circular buffer. The WTRU may select a plurality of bits for transmission from the interleaved bits.

Abstract: Systems, methods, and instrumentalities are described herein that may be used for reduced complexity polar encoding and decoding. There may be a set of encoding nodes to be used for polar encoding. An encoding node may be associated with a bit index and/or a relaxation level. A relaxation attribute may be selected for the encoding node. A relaxation group may be determined based on the relaxation attributes. The relaxation group may include two encoding nodes associated with consecutive bit indexes, an initial relaxation level, and the first relaxation attribute. A final relaxation level may be determined. Relaxation may be performed on the encoding nodes in the relaxation group. For example, an XOR operation between the encoding nodes may be omitted. Relaxation may be performed on the encoding nodes associated with each relaxation level up to the final relaxation level.

Abstract: Systems, methods, and instrumentalities are disclosed for interleaving coded bits. A wireless transmit/receive unit (WTRU) may generate a plurality of polar encoded bits using polar encoding. The WTRU may divide the plurality of polar encoded bits into sub-blocks of equal size in a sequential manner. The WTRU may apply sub-block wise interleaving to the sub-blocks using an interleaver pattern. The sub-blocks associated with a subset of the sub-blocks may be interleaved, and sub-blocks associated with another subset of the sub-blocks may not be interleaved. The sub-block wise interleaving may include applying interleaving across the sub-blocks without interleaving bits associated with each of the sub-blocks. The WTRU may concatenate bits from each of the interleaved sub-blocks to generate interleaved bits, and store the interleaved bits associated with the interleaved sub-blocks in a circular buffer. The WTRU may select a plurality of bits for transmission from the interleaved bits.

Abstract: Methods, apparatuses and systems are provided for constructing and modulating polar codes. Such procedures may involve identifying nonuniform channel conditions, selecting a modulation order, configuring a plurality of component codes and incremental ratios for Unequal Error Protection (UEP), identifying initial code construction parameters for each component code, calculating modified code construction parameters based on the incremental ratios for UEP, and encoding the component polar codes according to the modified construction parameters. Each component code may be comprised of a plurality of input bits. The initial and modified code construction parameters may include a number of unfrozen and frozen input bits, and identifying a number of unfrozen and frozen input bits may involve calculating and comparing reliability values for each bit. Calculating and comparing reliability values for each bit may involve applying a Polarization Weight (PW)-based method.

Abstract: Systems, methods, and instrumentalities are described herein that may be used for reduced complexity polar encoding and decoding. There may be a set of encoding nodes to be used for polar encoding. An encoding node may be associated with a bit index and/or a relaxation level. A relaxation attribute may be selected for the encoding node. A relaxation group may be determined based on the relaxation attributes. The relaxation group may include two encoding nodes associated with consecutive bit indexes, an initial relaxation level, and the first relaxation attribute. A final relaxation level may be determined. Relaxation may be performed on the encoding nodes in the relaxation group. For example, an XOR operation between the encoding nodes may be omitted. Relaxation may be performed on the encoding nodes associated with each relaxation level up to the final relaxation level.

Abstract: Systems, methods, and instrumentalities are disclosed for narrowband (NB) LTE operation. A WTRU may receive a first downlink data transmission, for example, via a physical downlink shared channel (PDSCH). The WTRU may determine to send a hybrid automatic repeat request (HARQ) acknowledgment (ACK) in response to receipt of the first downlink data transmission. The WTRU may transmit a first uplink reference signal. The WTRU may indicate the HARQ-ACK using a first cyclic shift index that is applied to the first uplink reference signal. The WTRU may determine to send a HARQ negative ACK (HARQ-NACK), for example, on a condition that a second downlink data transmission is not correctly received. The WTRU may send a second uplink reference signal. The WTRU may indicate the HARQ-NACK using a second cyclic shift that is applied to the second uplink reference signal.

Abstract: Systems, methods, and instrumentalities are disclosed for narrowband (NB) LTE operation. A WTRU may receive a first downlink data transmission, for example, via a physical downlink shared channel (PDSCH). The WTRU may determine to send a hybrid automatic repeat request (HARQ) acknowledgment (ACK) in response to receipt of the first downlink data transmission. The WTRU may transmit a first uplink reference signal. The WTRU may indicate the HARQ-ACK using a first cyclic shift index that is applied to the first uplink reference signal. The WTRU may determine to send a HARQ negative ACK (HARQ-NACK), for example, on a condition that a second downlink data transmission is not correctly received. The WTRU may send a second uplink reference signal. The WTRU may indicate the HARQ-NACK using a second cyclic shift that is applied to the second uplink reference signal.