Patent Description:
Wireless communication technologies are moving the world toward an increasingly connected and networked society. The rapid growth of wireless communications and advances in technology has led to greater demand for capacity and connectivity. Other aspects, such as energy consumption, device cost, spectral efficiency, and latency are also important to meeting the needs of various communication scenarios. In comparison with the existing wireless networks, next generation systems and wireless communication techniques need to provide support for an increased number of users and devices, as well as support for different code rates and differently sized payloads, thereby improving coverage enhancements.

<CIT> and <NPL>" are prior art documents related to cyclic shift design for PUCCH sequences.

This document relates to methods, systems, and devices for cyclic shift based mapping schemes for uplink control transmissions in mobile communication technology, including 5th Generation (<NUM>) and New Radio (NR) communication systems.

There is an increasing demand for fourth generation of mobile communication technology (<NUM>, the 4th Generation mobile communication technology), Long-term evolution (LTE, Long-Term Evolution), Advanced long-term evolution (LTE-Advanced/LTE-A, Long-Term Evolution Advanced) and fifth-generation mobile communication technology (<NUM>, the 5th Generation mobile communication technology). From the current development trend, <NUM> and <NUM> systems are studying the characteristics of supporting enhanced mobile broadband, ultra-high reliability, ultra-low latency transmission, and massive connectivity.

As fundamental building components to enable an NR system, the Physical Uplink Control Channel (PUCCH) and/or the Physical Shared Uplink Channel (PUSCH) are utilized to convey Uplink Control Information (UCI), which includes:.

In LTE, PUCCH is transmitted in one or more Physical Resource Blocks (PRB) at the edges of the system bandwidth, following a mirrored pattern with slot level frequency hopping within a subframe so as to maximize the frequency diversity. In NR, more flexible PUCCH structures need to be considered towards targeting different applications and use cases, especially for the support of low latency application such as URLLC.

If a UE is not transmitting on the PUSCH, and the UE is transmitting UCI in a PUCCH using, for example, the following formats:.

In some embodiments, for PUCCH formats supporting more than <NUM> bits, two coding schemes are applied depending on the payload size of the UCI, e.g., a block code based on Reed-Muller Codes is applied when the input payload size is between <NUM> to <NUM> bits, and Polar codes are used when larger than <NUM> bits. Since block codes are not the optimal coding scheme at low code rates for small to medium payload, embodiments of the disclosed technology advantageously provide enhanced performance in these cases, especially in coverage enhancement scenarios.

<FIG> shows an example of a wireless communication system (e.g., an LTE, <NUM> or New Radio (NR) cellular network) that includes a BS <NUM> and one or more user equipment (UE) <NUM>, <NUM> and <NUM>. In some embodiments, the uplink transmissions (<NUM>, <NUM>, <NUM>) include cyclically-shifted base sequences that constitute the mapping scheme for the uplink control transmissions. The UE may be, for example, a smartphone, a tablet, a mobile computer, a machine to machine (M2M) device, a terminal, a mobile device, an Internet of Things (IoT) device, and so on.

The present document uses examples from the 3GPP New Radio (NR) network architecture and <NUM> protocol only to facilitate understanding and the disclosed techniques and embodiments may be practiced in other wireless systems that use different communication protocols than the 3GPP protocols.

In some embodiments, a PUCCH format can be configured to occupy <NUM> resource block (RB) in the frequency-domain and <NUM> symbols in the time-domain, as shown in the example in <FIG>. The short sequence used in the frequency-domain is a length-<NUM> sequence. The short sequence is defined by a cyclic shift ncs of a base sequence ru(i) according to: <MAT>.

Herein, MZC is the length of the sequence and MZC = <NUM> for <NUM> RB. Multiple sequences are defined from a single base sequence through different values of ncs.

In some embodiments, the low-PAPR (peak-to-average-power ratio) sequences defined in current NR specification can be reused for the base sequence ru(i), given by: <MAT>.

In an example, the value of ϕ(i) is given as shown in Table <NUM> below.

In some embodiments, a combination set m {<u(n,m),ncs(n,m)>, n = <NUM>, <NUM>, <NUM>,. , N-<NUM>} is used to represent one symbol (or bit) of information. Embodiments of the disclosed technology are configured for small to medium payload sizes, e.g., <NUM>-<NUM> bits, and thus, combinations based on cyclic shifts alone may be sufficient because <NUM>N » <NUM>M when N=<NUM> and M=<NUM>. Herein, u(n, m) = u(n', m), n, n'= <NUM>,<NUM>,<NUM>,. N -<NUM>, n ≠ n', and the combination set m can be simplified as { ncs(n, m), n = <NUM>, <NUM>, <NUM>,. , N-<NUM>}. According to some embodiments, the information that is carried on the PUCCH has a one-to-one mapping to the combination set, regardless of whether the information is expressed as a bit sequence or converted to a decimal value.

In some embodiments, different cyclic shifts are used for different time domain symbols to represent different information. As shown in <FIG>, a sequence z(·) to be mapped over the assigned resource for PUCCH transmission can be obtained according to: <MAT>.

Herein, N is the number of OFDM symbols used for the PUCCH format (with N=<NUM> in this example). In some embodiments, the sequence z(·) can be mapped in a frequency-first time-second order over the assigned resource of the PUCCH. In other embodiments, it may be mapped in a time-first, frequency-second order over the assigned resource of the PUCCH.

In this manner, different uplink control information can be indicated by different combination sets (or equivalently, different CS hopping sequences ncs(n, m)) to generate the sequence z(·) for the PUCCH transmission.

Some embodiments of the disclosed technology define a mapping between the uplink control information and a CS hopping sequence ncs(n, m) used for short sequences transmitted on each time-domain symbol for the PUCCH. Given that the payload of the uplink control information varies from <NUM> to <NUM> bits, different numbers of CS hopping sequences may be needed to support the varying payload size. With regard to notation, a length of the payload of the UCI is denoted as M bits, and the number of CS hopping sequences is assumed to be NCSHop = <NUM>M.

According to the claimed invention, the cyclic shift used for symbol index n for the UCI bits m (denoted by its decimal value) is determined as: <MAT> or <MAT>.

Herein, B is the number of cyclic shifts used for a base sequence, A and D are constants greater than zero, n' and C are constants greater than zero or functions based on the values of m and/or n, and ncs(n, m) = M(Tcs(n, m)) denotes the mapping between Tcs(n, m) and ncs, wherein M(·) outputs the cyclic shift of its argument, which is used for the sequence generation.

In an example, B = MZC = <NUM>, which is equal to the length of the sequence of z(·). In this case, all the cyclic shifts available for the sequence are used, and the mapping between Tcs(n, m) and ncs can be simplified as ncs = Tcs(n, m).

In another example, B = <NUM>, which is smaller than the length of the sequence of z(·). In this case, not all the cyclic shifts available for the sequence are used, and the mapping between Tcs(n, m) and ncs can be predefined. As an example, the mapping between Tcs(n, m) and ncs can be predefined as shown in Table <NUM>.

In some embodiments, A and D are selected from the prime numbers between <NUM>,<NUM> to <NUM>,<NUM>, e.g., they can selected from Table <NUM>. In other embodiments, a numerical search may be performed to determine allowable values of A and D.

In some embodiments, C is a UE-specific parameter. In an example, C may be related to the Cell Radio Network Temporary Identifier (C-RNTI) of the UE.

In some embodiments, the number of identical elements in the same location in any pair of CS hopping sequences within the CS hopping pattern (which refers to the set of CS hopping sequences) is denoted as K. The maximum value of K is also illustrated in Table <NUM> for different combinations of (A, D, m) assuming n' = <NUM>, K = <NUM>, B =<NUM>, and ncs = Tcs(n, m).

In another example, Table <NUM> shows the cyclic shift sequences (ncs) for the case with A = <NUM>, D = <NUM>, n' = <NUM>, K = <NUM>, B =<NUM>, and ncs = Tcs(n, m).

In yet another example, Table <NUM> shows the cyclic shift sequences (ncs) for the case with A = <NUM>, D = <NUM>, n' = <NUM>, K = <NUM>, B =<NUM>, and ncs = Tcs(n, m).

Table <NUM>-<NUM> shows examples of cyclic shift sequences wherein a cyclic shift for an n-th symbol is based on the cyclic shift for an (n-<NUM>)-th symbol, which advantageously ensures that if there is an identical value in the k-th position, then there will be a different value in the (k+<NUM>)-th position. This results in consistently avoiding the case with two consecutive positions being identical across two symbols.

In some embodiments, and for a PUCCH with N1 symbols (with N1 < N), the CS hopping pattern can be truncated based on the basic pattern to meet the target length. In an example, the CS mapping on first N1 symbols of the N symbols are used.

In some embodiments, the CS hopping sequences described herein can be the initial CS hopping sequence for sequence generation. A cell-specific symbol-based CS hopping sequence can be applied on top of the initial CS hopping sequence.

In some embodiments, a PUCCH format can be configured to occupy <NUM> resource block (RB) in the frequency-domain and <NUM> symbols in the time-domain. The short sequence used in the frequency-domain is a length-<NUM> sequence. The short sequence is defined by a cyclic shift ncs of a base sequence ru(i) according to Equation <NUM>. The low-PAPR sequences defined in current NR specification can be reused for the base sequence ru(i), as defined in Equation <NUM>, and wherein the value of ϕ(i) is as shown in Table <NUM>.

According to an example outside the scope of the claimed embodiment, the cyclic shift used in symbol index n for the UCI bits m (denoted by a decimal value) can be expressed by: <MAT> where c(k) is a binary sequence and defined as: <MAT> where Nc is an integer and the first m-sequence x<NUM>(k) shall be initialized with x<NUM>(<NUM>) = <NUM>, x<NUM>(<NUM>) = x<NUM>(<NUM>) =. = x<NUM>(<NUM>) = <NUM>. The initialization of the second m-sequence x<NUM>(k), is dependent on the UCI. For example, if the UCI bits are [a<NUM>,a<NUM>,,. , aM -<NUM>], then the initialization for x<NUM>(k) will be: x<NUM>(<NUM>) = a<NUM>, x<NUM> (<NUM>) = a<NUM>, x<NUM> (<NUM>) = a<NUM>,. , x<NUM>(M -<NUM>) = aM-<NUM>, x<NUM> (M) = x<NUM> (M + <NUM>) =. = x<NUM> (<NUM>) = <NUM>.

In an example, Nc is selected from Table <NUM>, which also shows the maximum value of K for different combinations of (Nc, m).

In an example, Table <NUM> shows the cyclic shift sequences (ncs) for the case with Nc = <NUM> and B = <NUM>.

Tables <NUM> and <NUM> show examples wherein the cyclic shift depends on a pseudorandom sequence. In the example described, the pseudorandom sequence is a maximal length sequence (also referred to as an m-sequence), which is generated using maximal linear feedback shift register (LFSR).

<FIG> shows an example of a wireless communication method <NUM> for cyclic shift based mapping schemes for uplink control transmissions. The method <NUM> includes, at operation <NUM>, transmitting, by a wireless device over a control channel, an M-bit payload using N symbols, wherein M and N are positive integers.

According to the claimed embodiment, each of the N symbols is represented using a base sequence (u(n, m)) and a cyclic shift (ncs(n, m)) of the base sequence, n = <NUM>, <NUM>,. (N-<NUM>) indexes a symbol in the N symbols, m = <NUM>, <NUM>,. (<NUM>M-<NUM>) indexes a combination set, m and n are non-negative integers, the cyclic shift for a j-th symbol is based on a cyclic shift for a (j-<NUM>)-th symbol, and j = <NUM>, <NUM>,. (N-<NUM>) is a positive integer. In other embodiments, m is selected from the values <NUM>, <NUM>,. (<NUM>M-<NUM>) and indexes a combination set.

According to the claimed embodiment, the cyclic shift (ncs(n, m)) of the base sequence is determined as ncs(n, m) = M(Tcs(n, m)) , Tcs(n, m) = mod(Yn, B), Yn = mod(AYn-<NUM>, D), Y-<NUM> = m + C, wherein Yi is an i-th symbol, and wherein A, B, C, and D are positive integers, or the cyclic shift (ncs(n, m)) of the base sequence is determined as ncs(n, m) = M(Tcs(n, m)), Tcs(n, m) = mod(Yn+n, B), Yn = mod(AYn-<NUM>, D), Y-<NUM> = m + C, wherein Yi is an i-th symbol, and wherein A, B, C, D, and n' are positive integers.

In some embodiments, B is a number of cyclic shifts used for the base sequence.

In some embodiments, C is a predetermined constant.

In some embodiments, C is a parameter specific to the wireless device.

In some embodiments, C is a function of a cell radio network temporary identifier (C-RNTI) associated with the wireless device.

In some embodiments, A and D are prime numbers.

In some embodiments, (A, D) is selected from the group consisting of (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), (<NUM>, <NUM>), and (<NUM>, <NUM>).

According to an example outside the scope of the claimed embodiment, each of the N symbols is represented using a base sequence (u(n, m)) and a cyclic shift (ncs(n, m)) of the base sequence, n = <NUM>, <NUM>,. (N-<NUM>) indexes a symbol in the N symbols, m = <NUM>, <NUM>,. (<NUM>M-<NUM>) indexes a combination set, m and n are non-negative integers, and the cyclic shift for each of the N symbols is based on one or more pseudorandom binary sequences. In other embodiments, m is selected from the values <NUM>, <NUM>,. (<NUM>M-<NUM>) and indexes a combination set.

In some embodiments, the cyclic shift (ncs(n, m)) of the base sequence is determined as <MAT>, wherein the one or more pseudorandom binary sequences comprise c(k), x<NUM>(k) and x<NUM>(k), which are defined as c(k) = mod(x<NUM>(k + Nc) + x<NUM>(k + Nc), <NUM>), x<NUM>(k + <NUM>) = mod(x<NUM> (k + <NUM>) + x<NUM>(k), <NUM>), x<NUM>(k + <NUM>) = mod(x<NUM>(k + <NUM>) + x<NUM>(k + <NUM>) + x<NUM>(k + <NUM>) + x<NUM>(k), <NUM>), wherein Nc is a positive integer.

In some embodiments, x<NUM>(k) is initialized as x<NUM>(<NUM>) = <NUM>, x<NUM>(<NUM>) = x<NUM>(<NUM>) = ··· = x<NUM>(<NUM>) = <NUM>.

In some embodiments, Nc is equal to <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>.

In some embodiments, an initialization of x<NUM>(k) is based on an uplink control information (UCI).

In some embodiments, the UCI comprises a bit sequence [a<NUM>, a<NUM>,. , aM-<NUM>], and wherein x<NUM>(k) is initialized as x<NUM>(<NUM>) = a<NUM>, x<NUM>(<NUM>) = a<NUM>,x<NUM>(<NUM>) = a<NUM>, ··· , x<NUM>(M - <NUM>) = aM-<NUM>, and x<NUM>(M) = x<NUM>(M + <NUM>) = ··· = x<NUM>(<NUM>) = <NUM>.

<FIG> shows another example of a wireless communication method <NUM> for cyclic shift based mapping schemes for uplink control transmissions. The method <NUM> includes, at operation <NUM>, receiving, by a network node from a wireless device over a control channel, an M-bit payload on N symbols, wherein M and N are positive integers.

The method <NUM> includes, at operation <NUM>, transmitting, subsequent to the receiving, one or more subsequent communications to the wireless device over a data channel.

According to the claimed embodiment, each of the N symbols is represented using a base sequence (u(n, m)) and a cyclic shift (ncs(n, m)) of the base sequence, n = <NUM>, <NUM>,. (N-<NUM>) indexes a symbol in the N symbols, m = <NUM>, <NUM>,. (<NUM>M-<NUM>) indexes a combination set, m and n are non-negative integers, the cyclic shift for a j-th symbol is based on a cyclic shift for a (j-<NUM>)-th symbol, and j = <NUM>, <NUM>,. (N-<NUM>) is a positive integer.

According to an example outside of the scope of the claimed embodiment, each of the N symbols is represented using a base sequence (u(n, m)) and a cyclic shift (ncs(n, m)) of the base sequence, n = <NUM>, <NUM>,. (N-<NUM>) indexes a symbol in the N symbols, m = <NUM>, <NUM>,. (<NUM>M-<NUM>) indexes a combination set, m and n are non-negative integers, and the cyclic shift for each of the N symbols is based on one or more pseudorandom binary sequences.

In some embodiments, the <NUM>M combination sets are configured or predefined such that at most K elements are identical between any two combination sets of the <NUM>M combination sets, and wherein K is a non-negative integer.

In some embodiments, each of the at most K elements has an identical relative location in each of the any two combination sets.

In some embodiments, the transmitting is performed over a set of resources of the control channel, and wherein a mapping over the set of resources is in a frequency-first time-second order.

In some embodiments, the control channel is a PUCCH.

In some embodiments, the combination set comprises the base sequence and the cyclic shift used to represent a corresponding one of the N symbols.

In some embodiments, the N symbols are modulated using an orthogonal frequency division multiplexing (OFDM) modulation over the plurality of subcarriers.

In some embodiments, the N symbols are modulated using Discrete Fourier Transform spread orthogonal frequency division multiplexing (DFT-S-OFDM) modulation over the plurality of subcarriers.

<FIG> is a block diagram representation of a portion of an apparatus, in accordance with some embodiments of the presently disclosed technology. An apparatus <NUM>, such as a base station or a wireless device (or UE), can include processor electronics <NUM> such as a microprocessor that implements one or more of the techniques presented in this document. The apparatus <NUM> can include transceiver electronics <NUM> to send and/or receive wireless signals over one or more communication interfaces such as antenna(s) <NUM>. The apparatus <NUM> can include other communication interfaces for transmitting and receiving data. Apparatus <NUM> can include one or more memories (not explicitly shown) configured to store information such as data and/or instructions. In some implementations, the processor electronics <NUM> can include at least a portion of the transceiver electronics <NUM>. In some embodiments, at least some of the disclosed techniques, modules or functions are implemented using the apparatus <NUM>.

Claim 1:
A method for wireless communication, comprising:
transmitting, by a wireless device over a control channel, an M-bit payload using N symbols, wherein M and N are positive integers,
wherein each of the N symbols is represented using a base sequence u(n, m) and a cyclic shift ncs(n, m) of the base sequence,
wherein n = <NUM>, <NUM>, ... (N-<NUM>) indexes a symbol in the N symbols,
wherein m = <NUM>, <NUM>, ... (<NUM>M-<NUM>) indexes a combination set m {<u(n,m),ncs(n,m)>, n = <NUM>, <NUM>, <NUM>, ..., N-<NUM>} of the base sequence and the cyclic shift,
wherein m and n are non-negative integers, and: the cyclic shift (ncs(n, m)) of the base sequence is determined as:
ncs(n, m) = M(Tcs(n, m)), wherein M(·) outputs the cyclic shift of its argument, <MAT> <MAT> <MAT>
wherein Yi is an i-th symbol, and wherein A, B, C, D, and n' are positive integers.