# US 9,883,483 B2 · Systems and methods for coexistence of MBMS and VoIP services

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- Number: US 9,883,483 B2
- Document ID: US9883483B2
- Status: Granted
- Kind: B2
- Application number: 14/490,544
- Filed: 2014-09-18
- Published: 2015-12-31
- Granted: 2018-01-30
- Earliest claimed: 2014-06-25
- Assignees: Telefonaktiebolaget L M Ericsson (publ)
- Applicants: Telefonaktiebolaget L M Ericsson (publ)
- Inventors: Chandra Sekhar Bontu; Prabaharan Kanesalingam
- Web page: https://patentgrep.com/patent/US9883483B2

## CPC

- H04W 72/0446: Resources in time domain, e.g. slots or frames
- H04L 65/611: for multicast or broadcast (systems for broadcast or conference H04L12/18; arrangements for broadcast or distribution combined with broadcast H04H20/00; arrangements for broadcast applications with a direct linkage to broadcast information or to broadcast space-time H04H60/00; selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS], H04W4/06)
- H04M 7/0093: {signalling arrangements in networks}
- H04W 72/30: Resource management for broadcast services
- H04W 76/28: Discontinuous transmission [DTX]; Discontinuous reception [DRX]
- H04W 24/02: Arrangements for optimising operational condition
- Y02B 70/30: Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
- Y02D 30/70: in wireless communication networks
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE

## Abstract

Systems and methods for coexistence of Multimedia Broadcast Multicast Services (MBMS) and Voice over Internet Protocol (VoIP) services are disclosed. In one embodiment, a method of operation of a network node in a cellular communications network is provided. The method includes determining a number of MBMS subframes for an MBMS allocation period. The method also includes, for each MBMS subframe of the number of MBMS subframes, assigning a frame number and a subframe number for the MBMS subframe such that a probability of a VoIP packet transmission during the MBMS subframe is mitigated. By mitigating the probability that a VoIP packet transmission occurs during a scheduled MBMS subframe, a VoIP user equipment (UE) may miss fewer packets and/or experience reduced battery drain.

## Claims

### Claim 1

A method of operation of a network node in a cellular communications network, comprising:
obtaining a pattern of special subframes where the special subframes in the pattern of special subframes are selected from the group consisting of Multimedia Broadcast Multicast Service, MBMS, subframes, Almost Blank Subframes, ABS, New Carrier Type, NCT, subframes, and subframes assigned for Positioning Reference Signals, PRS;
receiving a request for a Voice over Internet Protocol, VoIP, Radio Access Bearer, RAB, from a user equipment, UE; and
determining one or more discontinuous reception, DRX, parameters for the VoIP RAB based on the pattern of special subframes.

### Claim 2 (depends on 1)

The method of claim 1 wherein determining the one or more DRX parameters for the VoIP RAB comprises determining the one or more DRX parameters for the VoIP RAB based on the pattern of special subframes such that a performance metric is optimized.

### Claim 3 (depends on 1)

The method of claim 1 wherein determining the one or more DRX parameters for the VoIP RAB comprises determining the DRX offset parameter for the VoIP RAB based on the pattern of special subframes.

### Claim 4 (depends on 3)

The method of claim 3 wherein determining the DRX offset parameter for the VoIP RAB comprises determining the DRX offset parameter for the VoIP RAB based on the pattern of special subframes such that packet delay for the VoIP RAB is reduced as compared to the packet delay for the VoIP RAB with a DRX offset parameter not determined based on the pattern of special subframes.

### Claim 5 (depends on 1)

The method of claim 1 wherein determining the DRX offset parameter for the VoIP RAB comprises determining a DRX offset parameter for the VoIP RAB such that, for each special subframe in the pattern of special subframes, the DRX offset parameter will not coincide with the special subframe.

### Claim 6 (depends on 1)

The method of claim 1 wherein determining the DRX offset parameter for VoIP RAB comprises determining the DRX offset parameter for the VoIP RAB such that a probability of subframe numbers which satisfy the criterion DRX offset=mod(subframe number, DRX period) being a special subframe is less than a threshold.

### Claim 7 (depends on 6)

The method of claim 6 wherein the threshold is defined based on a VoIP packet delay budget.

### Claim 8 (depends on 6)

The method of claim 6 wherein the threshold is dependent on the probability that the subframe numbers which satisfy the criterion DRX offset+n=mod(subframe number, DRX period) being a special subframe, where n is less than DRX ON TIME.

### Claim 9 (depends on 1)

The method of claim 1 wherein determining the one or more DRX parameters for the VoIP RAB comprises determining a DRX ON TIME parameter for the VoIP RAB based on the pattern of special subframes such that power use for the UE is reduced as compared to the power use for the UE with a DRX ON TIME parameter not determined based on the pattern of special subframes.

### Claim 10 (depends on 9)

The method of claim 9 wherein determining the DRX ON TIME parameter for the VoIP RAB comprises determining the DRX ON TIME parameter for the VoIP RAB based on the pattern of special subframes such that power use for the UE is reduced as compared to the power use for the UE with the DRX ON TIME parameter not determined based on the pattern of special subframes.

### Claim 11 (depends on 9)

The method of claim 9 wherein determining the DRX ON TIME parameter for the VoIP RAB comprises:
determining whether one or more special subframes in the pattern of special subframes are scheduled to be received immediately after the VoIP RAB is scheduled to be received;
if no special subframes in the pattern of special subframes are scheduled to be received immediately after the VoIP RAB is scheduled to be received, setting the DRX ON TIME parameter for the VoIP RAB to a minimum value for the DRX ON TIME parameter; and
if the one or more special subframes in the pattern of special subframes are scheduled to be received immediately after the VoIP RAB is scheduled to be received, setting the DRX ON TIME parameter for the VoIP RAB to a value greater than the minimum value for the DRX ON TIME parameter.

### Claim 12 (depends on 1)

The method of claim 1 wherein determining the one or more DRX parameters for the VoIP RAB comprises:
selecting a value for a DRX offset parameter for the VoIP RAB;
determining whether the value for the DRX offset parameter for the VoIP RAB is suitable; and
in response to determining that the value is suitable, setting the DRX offset parameter for the VoIP RAB to the value.

### Claim 13 (depends on 12)

The method of claim 12 wherein selecting the value for the DRX offset parameter for the VoIP RAB comprises randomly selecting the value for the DRX offset parameter for the VoIP RAB.

### Claim 14 (depends on 12)

The method of claim 12 wherein selecting the value for the DRX offset parameter for the VoIP RAB comprises selecting the value for the DRX offset parameter for the VoIP RAB from a sorted list of values.

### Claim 15 (depends on 14)

The method of claim 14 wherein the sorted list of values is sorted by a probability that each value is suitable.

### Claim 16 (depends on 14)

The method of claim 14 wherein the sorted list of values is sorted by an average resource availability.

### Claim 17 (depends on 12)

The method of claim 12 wherein determining whether the value for the DRX offset parameter for the VoIP RAB is suitable comprises determining that the value is not suitable if the value corresponds to a special subframe in the pattern of special subframes.

### Claim 18 (depends on 17)

The method of claim 17 wherein determining whether the value for the DRX offset parameter for VoIP RAB is suitable comprises determining if the DRX offset parameter for the VoIP RAB such that a probability of subframe numbers which satisfy the criterion DRX offset=mod(subframe number, DRX period) being a special subframe is less than a threshold.

### Claim 19 (depends on 12)

The method of claim 12 wherein determining whether the value for the DRX offset parameter for the VoIP RAB is suitable comprises determining that the value is not suitable and the method further comprises determining whether setting the DRX offset parameter for the VoIP RAB to the value would cause an overload condition.

### Claim 20 (depends on 19)

The method of claim 19 wherein determining whether setting the DRX offset parameter for the VoIP RAB to the value would cause an overload condition comprises:
determining a probability that setting the DRX offset parameter for the VoIP RAB to the value would cause a number of simultaneously active VoIP RABs to exceed a maximum number of simultaneously active VoIP RABs allowed; and
determining that the value is not suitable if the probability exceeds a threshold.

### Claim 21 (depends on 20)

The method of claim 20 wherein determining the probability that setting the DRX offset parameter for the VoIP RAB to the value would cause the number of simultaneously active VoIP RABs to exceed the maximum number of simultaneously active VoIP RABs comprises determining the probability that setting the DRX offset parameter for the VoIP RAB to the value would cause the number of simultaneously active VoIP RABs to exceed the maximum number based on a number of VoIP RABs having a DRX offset parameter set to the value and a voice activity factor that is the proportion of time a VoIP RAB is likely to be active.

### Claim 22 (depends on 12)

The method of claim 12 further comprising:
in response to determining that the value for the DRX offset parameter for the VoIP RAB is not suitable, repeating the selecting, determining, and setting steps with a new value for the DRX offset parameter for the VoIP RAB that is different from the value.

### Claim 23 (depends on 12)

The method of claim 12 further comprising:
determining that no value is suitable for the DRX offset parameter for the VoIP RAB; and
in response to determining that no value is suitable for the DRX offset parameter for the VoIP RAB, denying the request for the VoIP RAB.

### Claim 24 (depends on 1)

The method of claim 1 wherein the cellular communications network is a Long Term Evolution, LTE, network.

### Claim 25

A network node in a cellular communications network, comprising:
a processor; and
a memory coupled to the processor, the memory containing instructions executable by the processor whereby the network node is operative to:
obtain a pattern of special subframes where the special subframes in the pattern of special subframes are selected from the group consisting of Multimedia Broadcast Multicast Service, MBMS, subframes, Almost Blank Subframes, ABS, New Carrier Type, NCT, subframes, and subframes assigned for Positioning Reference Signals, PRS;
receive a request for a Voice Over Internet Protocol, VoIP, Radio Access Bearer, RAB, from a user equipment, UE; and
determine one or more discontinuous reception, DRX, parameters for the VoIP RAB based on the pattern of special subframes.

### Claim 26 (depends on 25)

The network node of claim 25 wherein the network node is operative to determine the one or more DRX parameters for the VoIP RAB by being operative to determine the one or more DRX parameters for the VoIP RAB based on the pattern of special subframes such that a performance metric is optimized.