Enhanced 5G/6G Message Reliability with Guard-Space References
Phase noise is an unsolved, limiting factor for high frequency communications envisioned for 6G. Proposed herein are phase-tracking reference signals embedded in each guard-space of a message. The receiver can recalibrate the phase noise, and amplitude noise as well, with based on each guard-space reference signal, thereby providing extremely localized noise compensation including amplitude and phase distortions and including rapidly-varying frequency-dependent distortions characteristic of interference, on a symbol-by-symbol basis, at zero cost in message throughput and transmission power. The normal functions of a cyclic prefix in the guard-space can be provided by tailoring the guard-space reference signal, as detailed herein. Examples show how guard-space reference signals provide a fault-mitigating capability that is enabling to 6G mmWave objectives.
1 . A method for a wireless transmitter to transmit a message, the method comprising:
a) preparing a resource grid comprising resource elements, each resource element occupying one subcarrier in frequency and one symbol-time in time, each resource element comprising a guard-space interval followed by a message data interval; and
b) transmitting a message comprising resource elements;
c) wherein each resource element of the message comprises:
i) a demodulation reference configured in the guard-space interval; and
ii) a data signal, modulated according to bits of the message, configured in the message data interval.
2 . The method of claim 1 , wherein the message is transmitted according to 5G or 6G technologies.
3 . The method of claim 1 , wherein each data signal is modulated according to quadrature amplitude modulation (QAM) comprising an amplitude-modulated I-branch and an orthogonal amplitude-modulated Q-branch.
4 . The method of claim 3 , wherein each demodulation reference comprises a predetermined I-branch amplitude and a predetermined Q-branch amplitude.
5 . The method of claim 4 , wherein one branch, of the I-branch and the Q-branch of the demodulation reference, comprises zero transmission.
6 . The method of claim 4 , wherein one branch, of the I-branch and the Q-branch of the demodulation reference, comprises a predetermined amplitude larger than any amplitude of any branch of the message data.
7 . The method of claim 1 , wherein each data signal is modulated according to amplitude modulation multiplexed with phase modulation, the amplitude modulation according to predetermined amplitude levels, and the phase modulation according to predetermined phase levels.
8 . The method of claim 7 , wherein each demodulation reference comprises one of the predetermined amplitude levels and one of the predetermined phase levels.
9 . A method for a wireless receiver to receive a message, the method comprising:
a) determining a resource grid comprising resource elements, each resource element comprising a subcarrier in frequency and a symbol-time in time;
b) receiving a message comprising message resource elements, wherein each message resource element comprises a guard-space interval followed by a message data interval;
c) for each particular message resource element:
i) determining, in the guard-space of the particular resource element, a guard-space signal comprising a reference signal, the reference signal comprising a predetermined modulation parameter of a modulation scheme;
ii) determining, in the message data interval of the particular resource element, a message signal modulated according to the modulation scheme to encode bits of the message; and
iii) demodulating the message signal according to the predetermined modulation parameter.
10 . The method of claim 9 , wherein:
a) the modulation scheme is quadrature amplitude modulation (QAM) comprising an amplitude-modulated I-branch and an orthogonal amplitude-modulated Q-branch, and
b) the predetermined modulation parameter comprises a predetermined amplitude level of the QAM modulation scheme.
11 . The method of claim 9 , wherein:
a) the modulation scheme comprises amplitude modulation multiplexed with phase modulation; and
b) the predetermined modulation parameter comprises a predetermined amplitude level or a predetermined phase level, or both, of the modulation scheme.
12 . The method of claim 9 , wherein the reference signal comprises a phase-tracking reference signal configured to indicate a predetermined phase level plus phase noise.
13 . The method of claim 9 , wherein the demodulating the message signal comprises:
a) determining a plurality of modulation levels according to the predetermined modulation parameter; and
b) selecting a closest modulation level, of the plurality of modulation levels, closest to the message signal.
14 . The method of claim 9 , further comprising:
a) averaging the guard-space signals, or the predetermined modulation parameters of those guard-space signals, from a plurality of resource elements in a particular symbol-time.
15 . A method for mitigating phase noise, the method comprising:
a) receiving a message comprising message elements, each message element comprising a resource element of a resource grid, each message element comprising a guard-space interval followed by a message data interval;
b) for each particular message element:
i) determining, according to a guard-space signal in the guard-space of the particular message element, a modulation parameter comprising a predetermined branch amplitude of a quadrature amplitude modulation (QAM) modulation scheme, the modulation scheme comprising orthogonal amplitude-modulated branches, wherein the orthogonal amplitude-modulated branches of the guard-space signal comprise a reference I-branch and a reference Q-branch;
ii) calculating a phase rotation angle according to an arctangent of a ratio of an amplitude of the reference I-branch and an amplitude of the reference Q-branch;
iii) determining, according to a message data signal in the message data interval of the particular resource element, a data I-branch amplitude and a data Q-branch amplitude;
iv) calculating a data phase angle according to an arctangent of a ratio of the data I-branch amplitude and the data Q-branch amplitude; and
v) subtracting the phase rotation angle from the data phase angle, thereby determining a corrected phase angle.
16 . The method of claim 15 , further comprising:
a) calculating, according to the corrected branch angle, a corrected I-branch amplitude and a corrected Q-branch amplitude; and
b) demodulating the particular message element according to the corrected I-branch amplitude and the corrected Q-branch amplitude.
17 . The method of claim 15 , further comprising:
a) calculating, according to the corrected branch angle, a corrected I-branch amplitude and a corrected Q-branch amplitude;
b) calculating a corrected sum-signal amplitude comprising a square root of a sum of the corrected I-branch amplitude squared plus the corrected Q-branch amplitude squared; and
c) demodulating the particular message element according to the corrected sum-signal amplitude and the corrected phase angle.
18 . The method of claim 15 , wherein:
a) a first reference branch, of the reference I-branch and the reference Q-branch, is transmitted with zero amplitude; and
b) a second reference branch, of the reference I-branch and the reference Q-branch, is transmitted with a predetermined non-zero amplitude.
19 . The method of claim 15 , wherein:
a) a first reference branch, of the reference I-branch and the reference Q-branch, is transmitted with a first non-zero amplitude; and
b) a second reference branch, of the reference I-branch and the reference Q-branch, is transmitted with a second non-zero amplitude equal to the first non-zero amplitude.
20 . The method of claim 15 , wherein:
a) the guard-space signal is transmitted with a predetermined amplitude and a predetermined phase.