July 2013
doc.: IEEE 802.11-13/0880-00
Considering In-Device Coexistence
interference from WiFi point of view
Date: 2013-07-17
Authors:
Name
Affiliations
Address
Wei Hong
Renesas Mobile Room 712, Tower C South,
Phone
email
+8613911037638
[email protected]
No.2, KeXueYuan South
Road, Beijing, 100190, P.R.C
Insinöörinkatu 41, 36200
+358-503636632
Tampere Finland
Juho Pirskanen
Renesas Mobile
Dapeng Liu
CMCC
Beijing, China
juho.pirskanen@renesasmobil
e.com
+358-50-4876991 [email protected]
om
anna.pantelidou@renesasmobi
le.com
+86 13911788933 [email protected]
Timo Koskela
Renesas Mobile Elektroniikkatie 13, 90590
Fang Xie
Ge Liu
Luohui Xia
CMCC
CMCC
CATR
Beijing, China
Beijing, China
Beijing, China
[email protected]
[email protected]
+86-10-62300329 [email protected]
Lei Wen
CATR
Beijing, China
+86-10-62300329 [email protected]
Meng Yang
CATR
Beijing, China
+86-10-62300167 [email protected]
Oulu, Finland
Anna Pantelidou
Renesas Mobile Elektroniikkatie 13, 90590
Oulu, Finland
Submission
Slide 1
Wei Hong, Renesas Mobile Corporation
July 2013
doc.: IEEE 802.11-13/0880-00
Abstract
• Interference between WiFi and Cellular has been mentioned
by several companies [1][2][3][4], including 3rd harmonized
distortion and In-Device Coexistence (IDC) Interference for
WiFi working on 2.4GHz.
• This paper will discuss the IDC research background
finalized in 3GPP and the necessarity to consider to solve
IDC interference from WiFi point of view.
Submission
Slide 2
Wei Hong, Renesas Mobile Corporation
July 2013
doc.: IEEE 802.11-13/0880-00
In-Device Coexistence (IDC) history in 3GPP
• Firstly proposed by CMCC on RAN#48 Jun 1 – 4, 2010 in RP-100671
• First contribution on RAN2#70bis Jun 28 – Jul 2, 2012 about scenario
and modelling.
• First solution on RAN2#71 Aug 23-27, 2012.
• In RAN#53 Sep 13 - 16 2012, IDC is agreed as a WI and the Scope of
core part was revised in RP111355.
• Currently, this WI is finalized in R11.
Coexistence interference impact from LTE in B40 on WLAN
Submission
Coexistence interference impact on LTE in B40 from WLAN
Slide 3
Wei Hong, Renesas Mobile Corporation
July 2013
doc.: IEEE 802.11-13/0880-00
Applicable scenarios for IDC in 3GPP [5]
ANT#1
• Coexistence interference scenarios
– LTE coexisting with WiFi
– LTE coexisting with Bluetooth
– LTE coexisting with GNSS
ANT#2
ANT#3
Interference
from BT/WiFi
Interference
from LTE
LTE RF
GPS
Baseband
LTE
Baseband
GPS RF
BT/WiFi
RF
BT/WiFi
Baseband
• Summary of in-device coexistence interference scenarios
–
–
–
–
Case 1: LTE Band 40 radio Tx causing interference to ISM radio Rx;
Case 2: ISM radio Tx causing interference to LTE Band 40 radio Rx;
Case 3: LTE Band 7 radio Tx causing interference to ISM radio Rx;
Case 4: LTE Band 7/13/14 radio Tx causing interference to GNSS radio Rx.
ISM Band:
2400~2483.5MHz
WiFi Channels
Band 40:
2300~2400MHz
TDD Mode
Ch1
Ch7
Ch13
2401-2423
2431-2453
2461-2483
Ch2
Ch8
Ch14
2406-2428
2436-2458
2473-2495
Ch3
Ch9
2411-2433
2441-2463
Ch4
Ch10
2416-2438
2446-2468
Ch5
Ch11
2421-2443
2451-2473
Ch6
Ch12
2426-2448
2456-2478
Band 7 UL:
2500~2570MHz
FDD Mode
Band 38:
2570~2620MHz
TDD Mode
Band 7 DL:
2620~2690MHz
FDD Mode
All TDD in China
Bluetooth Channels
79 Channels: 2402~2480 MHz
Submission
Slide 4
Wei Hong, Renesas Mobile Corporation
July 2013
doc.: IEEE 802.11-13/0880-00
Usage scenarios
• LTE + WiFi portable router
– In this scenario, LTE is considered as a backhaul link to access the
Internet, and the connectivity is shared by other local users using WiFi.
The WiFi transceiver is operated as an AP and has full control on
frequency channel and transmitting power. it may be possible to avoid
interference to/from WiFi by moving the WiFi signal away from the LTE
band. If this is not sufficient, time domain solutions are applicable:
– The coexistence interference case 1-3 may happen in this usage scenario.
eNB
LTE+WiFi-AP
STA1
Submission
Slide 5
STA2
Wei Hong, Renesas Mobile Corporation
July 2013
doc.: IEEE 802.11-13/0880-00
Usage scenarios
• LTE + WiFi offload
– In this scenario, an LTE UE can also connect to WiFi to offload traffic
from LTE and the WiFi transceiver of the UE operates as a terminal (not
AP) in infrastructure mode. The WiFi radio has to keep listening to the
beacon signal transmitted from WiFi AP for maintaining connection.
– The coexistence interference case 1-3 may happen.
Submission
Slide 6
Wei Hong, Renesas Mobile Corporation
July 2013
doc.: IEEE 802.11-13/0880-00
Other Usage scenarios – Non WLAN related
• LTE + BT earphone (VoIP service)
– The voice traffic transmitted by BT is actually from/to LTE, where the
traffic activities between LTE and BT will be very similar because of the
end-to-end latency requirement.
– The coexistence interference case 1-3 may happen in this usage scenario.
• LTE + BT earphone (Multimedia service)
– Multimedia (e.g. HD video) is downloaded by LTE and audio is routed to
a BT headset.
– The coexistence interference case 1-3 may happen in this usage scenario.
• LTE + GNSS Receiver
– This usage scenario considers that the LTE UE is also equipped with the
GNSS (e.g. GPS) receiver to support location services.
– In this scenario, it can be expected that LTE UL transmissions cause
interference to the GNSS receiver.
– The coexistence interference case 4 may happen in this usage scenario.
Submission
Slide 7
Wei Hong, Renesas Mobile Corporation
July 2013
doc.: IEEE 802.11-13/0880-00
Solutions agreed in 3GPP
• FDM solution
– The UE will indicate which LTE frequencies are unusable due to in-device coexistence.
• TDM solutions based on DRX
– The UE provides the eNB with a desired Discontinuous Reception (DRX) pattern, e.g.
LTE ON/OFF pattern.
– It is up to the eNB to decide and signal the final DRX configuration to the UE based on
UE suggested TDM pattern and other possible criteria e.g. traffic type.
– DRX period provides time periods for WLAN to operate without in-device interference
• Autonomous denial solutions
– UE can autonomously deny LTE UL transmission due to some critical short-term event
receptions of ISM side, e.g. some events during WLAN connection-setup or other
important signalling.
– UE can also autonomously deny ISM transmissions to ensure successful reception of
important LTE signalling in order to ensure connectivity with the eNB, e.g. system
information, paging, synchronization signal, critical dedicated signalling, etc.
Submission
Slide 8
Wei Hong, Renesas Mobile Corporation
July 2013
doc.: IEEE 802.11-13/0880-00
Necessity to consider IDC from WiFi point of view
• There are two important usage scenarios where improvement in IDC side at
WiFi side would be beneficial.
eNB
LTE+WiFi-AP
STA2
STA1
• Some real world scenario
T
-L
Ba
ck
ha
TD
ul
TD-LTE Base Station
E
ul
TD
-L
T
E
ha
ck
Ba
MIFI inside
Submission
MIFI inside
Slide 9
Wei Hong, Renesas Mobile Corporation
July 2013
doc.: IEEE 802.11-13/0880-00
Necessity to consider IDC from WiFi point of view
• In China, 2500-2690MHz will be used for TDD
– One of the problem mentioned by CMCC in WNG presentation “11-13-0343r0” is
that “Interference from other systems, such as BT, Microwave, and other mobile
RATs (such as TD-LTE).”
• IDC feature defined in 3GPP is optional.
– Some LTE terminals may even not have this feature.
• IDC feature defined in 3GPP cannot optimize WiFi performance
1. 3GPP can’t control WiFi’s behaviour and can’t guarantee that the device’s WiFi
module can follow the TDM pattern decided by LTE eNB.
2. Even if the device’s WiFi module can follow the TDM pattern, the peer WiFi device
communicating with the device’s WiFi module is not aware the TDM pattern. The
peer WiFi device may still tx/rx with the device’s WiFi module during LTE ON
period, which will degrade WiFi performance due to high in-device interference.
• So we may need to consider how to solve the IDC interference from WiFi
side to ensure WiFi performance and consider it as part of TGmc.
Submission
Slide 10
Wei Hong, Renesas Mobile Corporation
July 2013
doc.: IEEE 802.11-13/0880-00
Proposed method
• The WiFi module of the device enduring In-Device Coexistence Interference
should indicate/covert the TDM pattern from LTE to its WiFi peer(s).
• For example:
– If the device operates as a LTE UE and as a WLAN AP:
• The AP will indicate the converted TDM pattern fitting WiFi timeline which is calculated from LTE
TDM pattern in Beacon frame, probe response frame, (re)association response frame or new Action
frame to STAs.
– If the device operates as a LTE UE and as a WLAN non-AP STA:
• The non-AP STA will indicate the converted TDM pattern fitting WiFi timeline which is calculated from
LTE TDM pattern in (re)association request frame or new Action frame to AP.
Submission
Slide 11
Wei Hong, Renesas Mobile Corporation
July 2013
doc.: IEEE 802.11-13/0880-00
Straw Poll
• Do you support to include proposed solution to solve IDC problem
from WiFi side?
• Y:
• N:
• A:
Submission
Slide 12
Wei Hong, Renesas Mobile Corporation
July 2013
doc.: IEEE 802.11-13/0880-00
References
[1]
[2]
[3]
[4]
[5]
11-13-0545-00 On Future Enhancements to 802.11 Technolog; Juho Pirskanen, et al.
11-13-0527-00 Carrier Oriented WiFi Cellular Offload; Laurent Cariou Orange, et al.
11-13-0534-00 Usage Models for Next Generation Wi-Fi; Osama Aboul-Magd, et. al.
11-13-0761-00 Interference Control Use Case for HEW; Dapeng Liu, et. al.
3GPP TR 36.816 V11.2.0, Study on signalling and procedure for interference
avoidance for in-device coexistence.
Submission
Slide 13
Wei Hong, Renesas Mobile Corporation