US-20260128749-A1 - METHOD AND NETWORK NODE FOR HANDLING TRANSMISSION OF NARROWBAND SIGNALS BETWEEN A RADIO PART AND A BASEBAND PART OF THE NETWORK NODE

US20260128749A1US 20260128749 A1US20260128749 A1US 20260128749A1US-20260128749-A1

Abstract

A method performed by a network node of a wireless communication network. The network node includes a radio part and a baseband part connected to the radio part via a communication interface, and has a plurality of antennas. The method includes obtaining, by the radio part, narrowband signals received at each of the plurality of antennas from a number of User Equipment, UE, wirelessly connected to the network node. The method further includes compressing, by the radio part, the obtained narrowband signals of the plurality of antennas so that the compressed narrowband signals as a group contains fewer number of bits than the obtained narrowband signals, wherein the compression is performed based on an individual compression error tolerance for each of at least some of the obtained narrowband signals, and sending, by the radio part, the compressed narrowband signals over the communication interface to the baseband part.

Inventors

Yang Zhang
Oskar Mauritz
Jing Rao

Assignees

TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

Dates

Publication Date: 20260507
Application Date: 20221006

Claims (20)

1 . A method performed by a network node of a wireless communication network, the network node comprising a radio part and a baseband part connected to the radio part via a communication interface, the network node having a plurality of antennas, the method comprising: obtaining, by the radio part, narrowband signals received at each of the plurality of antennas from a number of User Equipment, UE, wirelessly connected to the network node; compressing, by the radio part, the obtained narrowband signals of the plurality of antennas so that the compressed narrowband signals as a group contains fewer number of bits than the obtained narrowband signals, wherein the compression is performed based on an individual compression error tolerance for each of at least some of the obtained narrowband signals, and sending, by the radio part, the compressed narrowband signals over the communication interface to the baseband part.
2 . The method according to claim 1 , further comprising: determining, for each of the at least some of the obtained narrowband signals, the individual compression error tolerance based on a signal quality performance for the narrowband signal, the signal quality performance being a measure of signal quality versus decoding error rate or detection error rate.
3 . The method according to claim 2 , wherein the signal quality performance is Signal to Noise Ratio, SNR, performance and the SNR performance is a known relation between the SNR and Block Error Rate, BLER, for the narrowband signal, or a known relation between the SNR and missed detection rate.
4 . The method according to claim 2 , wherein the determining of compression error tolerance for each of the at least some of the narrowband signals comprises, for each signal: obtaining the signal quality performance for the narrowband signal; defining a performance requirement working point, SNR0, of the narrowband signal; obtaining a signal quality estimate for the narrowband signal; determining a tolerable signal quality loss, SNR_margin, based on the signal quality estimate and the SNR0, and wherein the compression is performed based on the determined SNR_margin.
5 . The method according to claim 4 , further comprising: determining a tolerable noise power increase, ΔPn, based on a current noise power, Pn, and the SNR_margin, and wherein the compression is performed based on the ΔPn.
6 . The method according to claim 4 , further comprising: selecting a compression method, out of a plurality of different compression methods, to be used in the compression based on the determined SNR_margin.
7 . The method according to claim 4 , wherein the signal quality estimate is an SNR estimate, and wherein the SNR estimate is obtained based on a signal power estimate and noise power estimate of the narrowband signal, based on used modulation and coding scheme, MCS, of the narrowband signal, based on power control information, based on SNR measured on a reference signal, or based on SNR statistics of earlier narrowband signals communicated between UEs and the network node.
8 . The method according to claim 1 , wherein a first of the obtained narrowband signals carrying a first type of physical channel is determined to be compressed with same compression method and same compression level as a second of the obtained narrowband signals carrying a second type of physical channel when the first and second narrowband signals are in the same narrowband receiver resource blocks.
9 . The method according to claim 1 , further comprising: determining compression error tolerance for a third of the obtained narrowband signals based on compression error tolerance or signal quality estimate of a fourth of the obtained narrowband signal preceding the third narrowband signal, the third and the fourth narrowband signals both relating to a first of the number of UEs.
10 . The method according to claim 1 , wherein the compressing is performed dynamically over time based on the individual compression error tolerance.
11 . A network node of a wireless communication network, the network node comprising a radio part and a baseband part interconnected via a communication interface, the network node having a plurality of antennas, the network node comprising a processing circuitry and a memory, the memory containing instructions executable by the processing circuitry, the network node is being operative to: obtain, by the radio part, narrowband signals received at each of the plurality of antennas from a number of User Equipment, UE, wirelessly connected to the network node; compress, by the radio part, the obtained narrowband signals of the plurality of antennas so that the compressed narrowband signals as a group contains fewer number of bits than the obtained narrowband signals, wherein the compression is performed based on an individual compression error tolerance for each of at least some of the obtained narrowband signals, and send, by the radio part, the compressed narrowband signals over the communication interface to the baseband part.
12 . The network node according to claim 11 , being further operative to: determine, for each of the at least some of the obtained narrowband signals, the individual compression error tolerance based on a signal quality performance for the narrowband signal, the signal quality performance being a measure of signal quality versus decoding error rate or detection error rate.
13 . The network node according to claim 12 , wherein the signal quality performance is Signal to Noise Ratio, SNR, performance and the SNR performance is a known relation between the SNR and Block Error Rate, BLER, for the narrowband signal, or a known relation between the SNR and missed detection rate.
14 . The network node according to claim 12 , being operative to determine the compression error tolerance for each of the at least some of the narrowband signals by, for each signal: obtaining the signal quality performance for the narrowband signal; defining a performance requirement working point, SNR0, of the narrowband signal; obtaining a signal quality estimate for the narrowband signal; and determining a tolerable signal quality loss, SNR_margin, based on the signal quality estimate and the SNR0, and wherein the network node is operative for performing the compression based on the determined SNR_margin.
15 . The network node according to claim 14 , being further operative to: determine a tolerable noise power increase, ΔPn, based on a current noise power, Pn, and the SNR_margin, and wherein the network node is operative to perform the compression based on the ΔPn.
16 . The network node according to claim 14 , being further operative for to: select a compression method, out of a plurality of different compression methods, to be used in the compression based on the determined SNR_margin.
17 . The network node according to claim 14 , wherein the signal quality estimate is an SNR estimate, and wherein the network node is operative to obtain the SNR estimate based on a signal power estimate and noise power estimate of the narrowband signal, based on used modulation and coding scheme, MCS, of the narrowband signal, based on power control information, based on SNR measured on a reference signal, or based on SNR statistics of earlier narrowband signals communicated between UEs and the network node.
18 . The network node according to claim 11 , operative to determine that a first of the obtained narrowband signals carrying a first type of physical channel is to be compressed with same compression method and same compression level as a second of the obtained narrowband signals carrying a second type of physical channel when the first and second narrowband signals are in the same narrowband receiver resource blocks.
19 . The network node according to claim 11 , being further operative to determine compression error tolerance for a third of the obtained narrowband signals based on compression error tolerance or signal quality estimate of a fourth of the obtained narrowband signal preceding the third narrowband signal, the third and the fourth narrowband signals both relating to a first of the number of UEs.
20 . (canceled)

Description

TECHNICAL FIELD The present disclosure relates generally to methods and network nodes in wireless communication networks for handling uplink narrowband signals to be transmitted from a radio part of the network node to a baseband part of the network node over an interface. The present disclosure further relates to computer programs and carriers corresponding to the above methods and radio parts. BACKGROUND Wireless communication network bitrate demand continues to increase. To further improve radio link quality so that higher bitrate/spectrum efficiency can be achieved, 3GPP 5th Generation (5G) networks rely on massive Multiple Input Multiple Output (MIMO) and beamforming techniques to direct beams sent between a base station, aka network node, and a wireless device, aka User Equipment (UE), and thereby improve coverage. Beamforming is performed by coherently combining radio frequency (RF) signals from small antenna elements. By phase-shifting and/or amplifying the signal into the antenna elements, the desired beam is formed. These techniques mitigate the problem of path loss by radically increasing the beam gain, e.g., via constructive interference of multiple, relatively low power beams. Thereby, the rated Equivalent Isotropic Radiated Power (EIRP) rating of mmW base stations is restored to usable levels. A network node that handles massive MIMO techniques is often realized as having a radio part and a baseband part interconnected via a communication interface, shortly “interface”. Functionality of the network node is split between the radio part and the baseband part. The radio part is connected to the plurality of antenna elements through which the network node wirelessly communicates with at least one UE. In massive MIMO, a large amount of antenna elements is used, each antenna element receiving a version of an uplink (UL) signal sent from a UE. All those received antenna signals are to be transported over the communication interface between the radio part and the baseband part. In addition, a large bandwidth is used. All together this puts huge challenges on the communication interface between the radio part and the baseband part. In other words, the demand on capacity over the communication interface between the radio part and the baseband part increases. So, there is a need to try to limit the amount of data that is sent over this communication interface. The radio part has a wideband receiver (WBR) for processing wideband signals. In addition, a narrowband receiver (NBR) for processing narrowband signals has been invented and inserted into the radio part to be used in e.g., an Advanced Antenna System (AAS) for various purposes. The NBR gives access to narrowband signals from the antenna elements with distributed beamforming. The NBR is designed for receiving and processing Physical Random-Access Channel (PRACH), Physical Uplink Control Channel (PUCCH), Sounding Reference Signal (SRS) and narrowband Physical Uplink Shared Channel (PUSCH) in parallel with the WBR processing UL payload data. As shown, the interface load is dependent on both WBR and NBR data streams, at least in periods. Any method that can lower the interface load but still maintain signal quality has huge benefits. SUMMARY It is an object of the invention to address at least some of the problems and issues outlined above. It is an object of embodiments of the invention to limit the interface load of an interface between a radio part and a baseband part of a network node. It is another object of embodiments to limit such interface load that depends on narrowband data streams or signals sent over the interface. It is possible to achieve these objects and others by using methods and network nodes as defined in the attached independent claims. According to one aspect, a method is provided that is performed by a network node of a wireless communication network. The network node comprises a radio part and a baseband part connected to the radio part via a communication interface. The network node has a plurality of antennas. The method comprises obtaining, by the radio part, narrowband signals received at each of the plurality of antennas from a number of UEs wirelessly connected to the network node. The method further comprises compressing, by the radio part, the obtained narrowband signals of the plurality of antennas so that the compressed narrowband signals as a group contains fewer number of bits than the obtained narrowband signals, wherein the compression is performed based on an individual compression error tolerance for each of at least some of the obtained narrowband signals. The method further comprises sending, by the radio part, the compressed narrowband signals over the communication interface to the baseband part. According to another aspect, a network node of a wireless communication network is provided. The network node comprises a radio part and a baseband part interconnected via a communication interface. The network node