Various multi-antenna solutions 2. Multi-Antenna Solutions in Vehicle ...
Multi‐Antenna Solutions in Vehicle Environment Hiro Onishi (Alpine Electronics Research of America, Inc.) Fanny Mlinarsky (octoScope, Inc.)
© 2014 Alpine Electronics, Inc. Not for commercial distribution.
1
INDEX
1. Introduction ‐ Various multi‐antenna solutions Various multi antenna solutions
2. Multi‐Antenna Solutions in Vehicle Environment ‐ Contributions in vehicle environment ‐ Factors affecting multi‐antenna performance ‐ Advantages and challenges ‐ Multi‐antenna performance in vehicle environment
3. Advanced Multi‐Antenna Solutions ‐ Multi‐User MIMO( M l i U MIMO(Multiple Input Multiple Output) ‐ CoMP(Cooperative Multi‐Points)
4 Next Steps 4. Next Steps 2
1. Introduction + How can we utilize advanced wireless technologies to we utilize advanced wireless technologies to automotive/ITS applications? + What is the challenge g for their implementation? p
Pictures: Courtesy of Dept. of Transportation
3
1. Introduction ‘MIMO’ concept exists long time ago, p g g , but it wasn’t being implemented till the 90’s.
~ B. Sklar, lecture, (Mar. 18 ’14, at CA state Univ. Long Beach) 4
1. Introduction Multi antenna solutions are keys for modern wireless technologies, Multi‐antenna solutions are keys for modern wireless technologies such as, 802.11n/ac, LTE and WiMax. a) Improve transmission reliability against channel impairments, a) Improve transmission reliability against channel impairments i.e. fading, multi‐path or interference. a
Tx
a
a
a
a
Rx
b) Increase transmission rate by using multi‐channels, without using additional wireless spectrum. a ba
Tx
b
a + b b + a
Rx
ba
Reference: L. Wang, Advances in Coordinated Multi‐Cell Multi‐User MIMO system, IEEE web seminar
5
1. Introduction Various multi‐antenna solutions Solutions
Rx diversity* Tx diversity*
Explanation Combine multiple received versions of the same signal in order to minimize PER(Packet Error Rate). Rate) Transmit different versions of the same signal in order to optimize reception of at least one of these versions. Use Tx diversity at the transmitting device in combination with Rx diversity at the receiving device.
Combination of Tx and Rx diversity* MIMO(Multi Input Multi Output) Transmit two or more data streams in the same channel. ‐ Spatial Multiplexing* Create a focused beam, thereby extending the range of the MIMO ‐ Beamforming* Closed‐loop** Pilot Signal (Antenna)***
link or enabling SM(Spatial Multiplexing). Feedback channel information from receiver to transmitter. (cf. Open‐loop) Transmit pilot signal from receiver to transmitter before data transmission. Transmitter adjust transmission parameter by using pilot signal.
Reference: *: F. Mlinarsky, Testing MIMO Radios, “Digi‐Key” web seminar, (Jan 27‐31, ’14 ) **: Y. Hara, et al., Basic Algorithm of Multi‐Antenna Technologies, Japan IEEE conference (’10) ***: D. Phan‐Huy, et al., Adaptive Large MISO Downlink with Predictor Antenna Array for very fast moving vehicles, IEEE ICCVE (Dec. ’13, Las Vegas, NV)
6
1. Introduction Various multi‐antenna solutions a) Rx diversity: Combine multiple received versions of the same signal in order to minimize PER(Packet Error rate). Typical diversity algorithms are ‐ Switching ‐ Selecting ‐ Combining: MRC(Maximal‐Ratio Combining) is typical. Æ Weighting: Zero‐Forcing weight, MMSE(Minimum Mean Square Error) weight, etc
Rx diversity
Reference: ‐ F. Mlinarsky, Testing MIMO Radios, “Digi‐Key” web seminar, (Jan 27‐31, ’14) ‐ wikipedia , Antenna diversity ‐ Y. Hara, et al., Basic Algorithm of Multi‐Antenna Technologies, Japan IEEE conference (’10)
7
1. Introduction Various multi‐antenna solutions b) Tx diversity: Transmit different versions of the same signal Transmit different versions of the same signal in order to optimize reception of at least one of these versions. Typical diversity algorithms are + STBC (Space Time Block Coding) – Alamouti code is one of them + STBC (Space Time Block Coding) code is one of them + SFBC (Space Frequency Block Coding ) + CDD (Cyclic Delay Diversity)
Tx diversity
Reference: F. Mlinarsky, Testing MIMO Radios, “Digi‐Key” web seminar (Jan 27‐31, ’14 )
8
1. Introduction Various multi‐antenna solutions c) Spatial Multiplexing Multiple signals on the same channel ( Multiple signals on the same channel (=same same space and same frequency space and same frequency) ) can be recognized as multiple original signals by receivers. Æ Increased spatial streams improve transmission reliability a d t a s ss o ate. and transmission rate. Spatial Multiplexing Received signal
H11
Sr1
St2
H22
Sr2
Tx
Rx
St1
Received signal
Transmitted signal
2 signals transmitted on same space and same frequency can be recognized by receivers
St1
H1
Sr1
St2
H2
Sr2
Rx
Wireless channel
Tx
Transmitted signal
Spatial Multiplexing ‐ Concept
Transmitter and receiver are linked by 2 spatial streams
Reference: The Cisco Learning Network, What is Spatial Multiplexing
9
1. Introduction Various multi‐antenna solutions d) Beamforming Focus RF beams by combining multiple phase‐locked antenna elements. Enhance transmission Æ Enhance reliability ‐ Transmission reliability p p g ‐ Spatial‐multiplexing Enhance signal to Enhance signal to Signal ‐3 desired direction
Beamforming ‐ example
Depress signal to unnecessary direction
Enhance spatial‐multiplexing Si l 2 Signal‐2
Signal 1 ‐1
Signal‐3
Reference: ‐ F. Mlinarsky, Testing MIMO Radios, “Digi‐Key” web seminar (Jan 27‐31, ’14) ‐ Y. Hara, et al., Basic Algorithm of Multi‐Antenna Technologies, Japan IEEE conference (’10)
10
1. Introduction Various multi‐antenna solutions e) Closed‐loop Receiver feedback channel information to transmitter. Receiver feedback channel information to transmitter. Æ Transmitter adjusts transmission parameters, by using feedback Information. cf Open‐loop cf. Open‐loop
Base‐ station
MIMO channel
Mobile terminal
Feedback (channel) ( ) information
Reference: Y. Hara, et al., Basic Algorithm of Multi‐Antenna Technologies, Japan IEEE conference (’10)
11
1. Introduction Various multi‐antenna solutions f) One example of ‘pilot antenna’ Receiver transmits pilot signal from a Receiver transmits pilot signal from a0(pilot antenna pilot antenna) to transmitter. ) to transmitter. Æ Transmitter sends data signal targeting a0. Æ Per vehicle speed, one of a0 ~ a3 receives the optimum data signal.
Reference: D. Phan‐Huy, et al., Adaptive Large MISO Downlink with Predictor Antenna Array for very fast moving vehicles, IEEE ICCVE (Dec. ’13, Las Vegas, NV)
12
2. Multi‐Antenna Solutions in Vehicle Environment Contributions in vehicle environment a) Improve transmission reliability against channel impairments, such as Doppler, fading, multi‐path or interference. pp , g, p Æ Contribute to automotive/ITS applications in various radio environments. (e.g. building canyon, tunnel, mountain/hilly area) b) Increase transmission rate (~ communication capacity). b) I i i ( i i i ) b.1) Quick response to transmit large data, i.e. map, traffic, music, movies, etc. b.2) In general, the size of safety messages (for crash‐warning) is very small, but more vehicles can communicate ‐ within pre‐defined duration (e.g. critical crash warning timing) ‐ in high density areas of communication modules (e.g. freeway intersection) Æ Large safety contribution! 13
2. Multi‐Antenna Solutions in Vehicle Environment Factors affecting multi‐antenna performance g p Factors
Explanation/Impact Function of several variables including device antenna spacing, antenna polarization and multipath
MIMO channel correlation Angular spread of the Related to correlation and strongly influenced by multipath in the channel received signal Device antenna spacing Related to angular spread and correlation and orientation Antenna polarization Vertical, horizontal or circular
Noise and Interference High noise power with respect to signal power results in low SNR (signal to noise ratio)
Motion of devices or M ti fd i multipath reflectors Delay spread of reflections
Causes Doppler spread of the signal Causes Doppler spread of the signal Causes clusters of reflections to arrive at the receiver at different times different times
Reference: F. Mlinarsky, Testing MIMO Radios, “Digi‐Key” web seminar (Jan 27‐31, ’14)
14
2. Multi‐Antenna Solutions in Vehicle Environment Advantages and challenges g g Advantages
FFreedom of antenna (array) size and d f t ( ) i d shape (compared to mobile phones or laptops) + Freedom of antenna spacing and orientation i t ti + Benefit of antenna polarization + Ease of ‘Beamforming’ to target to l large vehicle antennas with long distances hi l t ith l di t + Small MIMO channel correlation
Challenges
LLarger moving speed ( i d (compared to pedestrians) + Dynamic change of channel condition ‐ Difficulty in adjusting parameters for ‘Spatial multiplexing’ ‐ Difficulty of ‘Closed‐loop’ operation ‐ Difficulty of ‘Beamforming’ to target to vehicle antennas ‐ Dynamic change of antenna orientation + Large Doppler effects
15
2. Multi‐Antenna Solutions in Vehicle Environment Multi‐antenna performance in vehicle environment p What solutions fit each automotive/ITS application? Simulation ~ Fujitsu, “Text Proposal for MIMO and Tx Diversity Comparison Section”, (TSGR1#19(01)‐0410) in TSG‐RAN Working Group meeting (Feb. ’01, Las Vegas, NV)
Flat‐fading channel (3G) Tx‐closed‐loop diversity (30km/h)
FER
(Frrame‐error‐rate)
STTD (space‐time transmit diversity) ‐ Open‐loop Closed‐loop Tx diversity
4X4 MIMO (30km/h)
2X2 MIMO (30km/h)
Eb/No (dB)
(Energy‐bit to noise ratio)
16
2. Multi‐Antenna Solutions in Vehicle Environment Multi‐antenna performance in vehicle environment p ~ T. M. Fernandez‐Carames, et al., “Performance Evaluation of Multiple‐Antenna IEEE 802.11p Transceivers Using an FPGA‐based MIMO Vehicular Channel Emulator”, EURASIP Journal on Wireless Communications and Networking 2012, 2012:215 (Jul. ’12)
FER
(Frame‐error‐ratte)
Baseline: Frequency‐flat block fading Rayleigh channel (802.11p)
Minimum mean i i square error Maximum ratio combining
Maximum-likelihood detector
Alamouti Space‐time block code block code Quasi‐orthogonal Space‐Time Block Code
SNR (dB)
(Signal noise ratio)
1X4 SIMO 4X4 MIMO
17
2. Multi‐Antenna Solutions in Vehicle Environment Multi‐antenna performance in vehicle environment p
BER
(Bit‐error‐rate)
Vehicle‐to‐road in urban canyon (802.11p)
Minimum mean square error Maximum ratio combining
Maximum-likelihood detector
Alamouti Space‐time block code Quasi‐orthogonal Space‐time block code
1X4 SIMO 4X4 MIMO
SNR (dB)
(Signal noise ratio)
18
2. Multi‐Antenna Solutions in Vehicle Environment Multi‐antenna performance in vehicle environment p
FER
(Fram me‐error‐rate)
Vehicle‐to‐vehicle on‐coming vehicle in urban canyon (802.11p)
Minimum mean square error Maximum ratio combining
Maximum-likelihood detector
Alamouti Space‐time block code Quasi‐orthogonal Space‐time block code
1X4 SIMO
4X4 MIMO
SNR (dB) ( )
(Signal noise ratio)
Deeper numerical evaluations are required.
19
3. Advanced Multi‐Antenna Solutions Multi‐User MIMO(Multiple Input Multiple Output) Forming multiple focused beams or using Tx diversity techniques to enable simultaneous communications with multiple users( ~ devices). (Typically beamforming is done by a base station or an access point.)
Æ Increase total throughput of the transmissions to multiple users by spatially distributed transmission resources. (Single User) ‐ MIMO Base Station
MU(Multi‐User) ‐ MIMO Base Station Mobile Station‐1
Mobile Station‐2
Mobile Station
Mobile Station‐3
Reference: ‐ F. Mlinarsky, Testing MIMO Radios, (“Digi‐Key” web seminar, Jan 27‐31) ‐ Y. Hara, et al., Basic Algorithm of Multi‐Antenna Technologies, Japan IEEE conference (’10)
20
3. Advanced Multi‐Antenna Solutions CoMP(Cooperative Multi‐Points) Multiple base stations cooperate to transmit to single users or multiple users. Å CoMP was was originally invented for the improvement of the reception originally invented for the improvement of the reception in cell(coverage of base station)‐edges. Joint Processing
Coordinated Scheduling
Coordinated Beamforming CSI(Channel State Information) and data exchange between each base station Coordinated transmission to the mobile station
Reference: L. Wang, Advances in Coordinated Multi‐Cell Multi‐User MIMO system, (ieee web seminar)
21
4. Next Steps Because of the time limitation, Because of the time limitation we focused on introducing various multi‐antenna solutions. Near term planning: Conduct deeper numerical analysis of multi‐antenna solutions for each automotive or ITS application for each automotive or ITS application. Æ We are planning to show our progress at the next opportunity.
Longer term planning: Propose utilizing advanced multi‐antenna solutions, Propose utilizing advanced multi‐antenna solutions for automotive or ITS applications. Æ Study advantages and challenges on how to apply them to each automotive or ITS application each automotive or ITS application. 22
Thank you for your attention!! you for your attention!! Hiro Onishi Alpine Electronics Research of America, Inc. Al i El t i R h fA i I honishi@alpine‐la.com, Tel: +1‐310‐783‐7281
Fanny Mlinarsky octoScope, Inc. [email protected], Tel: +1‐978‐376‐5841 Slide design: g Mari Hatazawa mhatazawa@alpine‐la.com 23
© 2014 Alpine Electronics, Inc. Not for commercial distribution.
1
INDEX
1. Introduction ‐ Various multi‐antenna solutions Various multi antenna solutions
2. Multi‐Antenna Solutions in Vehicle Environment ‐ Contributions in vehicle environment ‐ Factors affecting multi‐antenna performance ‐ Advantages and challenges ‐ Multi‐antenna performance in vehicle environment
3. Advanced Multi‐Antenna Solutions ‐ Multi‐User MIMO( M l i U MIMO(Multiple Input Multiple Output) ‐ CoMP(Cooperative Multi‐Points)
4 Next Steps 4. Next Steps 2
1. Introduction + How can we utilize advanced wireless technologies to we utilize advanced wireless technologies to automotive/ITS applications? + What is the challenge g for their implementation? p
Pictures: Courtesy of Dept. of Transportation
3
1. Introduction ‘MIMO’ concept exists long time ago, p g g , but it wasn’t being implemented till the 90’s.
~ B. Sklar, lecture, (Mar. 18 ’14, at CA state Univ. Long Beach) 4
1. Introduction Multi antenna solutions are keys for modern wireless technologies, Multi‐antenna solutions are keys for modern wireless technologies such as, 802.11n/ac, LTE and WiMax. a) Improve transmission reliability against channel impairments, a) Improve transmission reliability against channel impairments i.e. fading, multi‐path or interference. a
Tx
a
a
a
a
Rx
b) Increase transmission rate by using multi‐channels, without using additional wireless spectrum. a ba
Tx
b
a + b b + a
Rx
ba
Reference: L. Wang, Advances in Coordinated Multi‐Cell Multi‐User MIMO system, IEEE web seminar
5
1. Introduction Various multi‐antenna solutions Solutions
Rx diversity* Tx diversity*
Explanation Combine multiple received versions of the same signal in order to minimize PER(Packet Error Rate). Rate) Transmit different versions of the same signal in order to optimize reception of at least one of these versions. Use Tx diversity at the transmitting device in combination with Rx diversity at the receiving device.
Combination of Tx and Rx diversity* MIMO(Multi Input Multi Output) Transmit two or more data streams in the same channel. ‐ Spatial Multiplexing* Create a focused beam, thereby extending the range of the MIMO ‐ Beamforming* Closed‐loop** Pilot Signal (Antenna)***
link or enabling SM(Spatial Multiplexing). Feedback channel information from receiver to transmitter. (cf. Open‐loop) Transmit pilot signal from receiver to transmitter before data transmission. Transmitter adjust transmission parameter by using pilot signal.
Reference: *: F. Mlinarsky, Testing MIMO Radios, “Digi‐Key” web seminar, (Jan 27‐31, ’14 ) **: Y. Hara, et al., Basic Algorithm of Multi‐Antenna Technologies, Japan IEEE conference (’10) ***: D. Phan‐Huy, et al., Adaptive Large MISO Downlink with Predictor Antenna Array for very fast moving vehicles, IEEE ICCVE (Dec. ’13, Las Vegas, NV)
6
1. Introduction Various multi‐antenna solutions a) Rx diversity: Combine multiple received versions of the same signal in order to minimize PER(Packet Error rate). Typical diversity algorithms are ‐ Switching ‐ Selecting ‐ Combining: MRC(Maximal‐Ratio Combining) is typical. Æ Weighting: Zero‐Forcing weight, MMSE(Minimum Mean Square Error) weight, etc
Rx diversity
Reference: ‐ F. Mlinarsky, Testing MIMO Radios, “Digi‐Key” web seminar, (Jan 27‐31, ’14) ‐ wikipedia , Antenna diversity ‐ Y. Hara, et al., Basic Algorithm of Multi‐Antenna Technologies, Japan IEEE conference (’10)
7
1. Introduction Various multi‐antenna solutions b) Tx diversity: Transmit different versions of the same signal Transmit different versions of the same signal in order to optimize reception of at least one of these versions. Typical diversity algorithms are + STBC (Space Time Block Coding) – Alamouti code is one of them + STBC (Space Time Block Coding) code is one of them + SFBC (Space Frequency Block Coding ) + CDD (Cyclic Delay Diversity)
Tx diversity
Reference: F. Mlinarsky, Testing MIMO Radios, “Digi‐Key” web seminar (Jan 27‐31, ’14 )
8
1. Introduction Various multi‐antenna solutions c) Spatial Multiplexing Multiple signals on the same channel ( Multiple signals on the same channel (=same same space and same frequency space and same frequency) ) can be recognized as multiple original signals by receivers. Æ Increased spatial streams improve transmission reliability a d t a s ss o ate. and transmission rate. Spatial Multiplexing Received signal
H11
Sr1
St2
H22
Sr2
Tx
Rx
St1
Received signal
Transmitted signal
2 signals transmitted on same space and same frequency can be recognized by receivers
St1
H1
Sr1
St2
H2
Sr2
Rx
Wireless channel
Tx
Transmitted signal
Spatial Multiplexing ‐ Concept
Transmitter and receiver are linked by 2 spatial streams
Reference: The Cisco Learning Network, What is Spatial Multiplexing
9
1. Introduction Various multi‐antenna solutions d) Beamforming Focus RF beams by combining multiple phase‐locked antenna elements. Enhance transmission Æ Enhance reliability ‐ Transmission reliability p p g ‐ Spatial‐multiplexing Enhance signal to Enhance signal to Signal ‐3 desired direction
Beamforming ‐ example
Depress signal to unnecessary direction
Enhance spatial‐multiplexing Si l 2 Signal‐2
Signal 1 ‐1
Signal‐3
Reference: ‐ F. Mlinarsky, Testing MIMO Radios, “Digi‐Key” web seminar (Jan 27‐31, ’14) ‐ Y. Hara, et al., Basic Algorithm of Multi‐Antenna Technologies, Japan IEEE conference (’10)
10
1. Introduction Various multi‐antenna solutions e) Closed‐loop Receiver feedback channel information to transmitter. Receiver feedback channel information to transmitter. Æ Transmitter adjusts transmission parameters, by using feedback Information. cf Open‐loop cf. Open‐loop
Base‐ station
MIMO channel
Mobile terminal
Feedback (channel) ( ) information
Reference: Y. Hara, et al., Basic Algorithm of Multi‐Antenna Technologies, Japan IEEE conference (’10)
11
1. Introduction Various multi‐antenna solutions f) One example of ‘pilot antenna’ Receiver transmits pilot signal from a Receiver transmits pilot signal from a0(pilot antenna pilot antenna) to transmitter. ) to transmitter. Æ Transmitter sends data signal targeting a0. Æ Per vehicle speed, one of a0 ~ a3 receives the optimum data signal.
Reference: D. Phan‐Huy, et al., Adaptive Large MISO Downlink with Predictor Antenna Array for very fast moving vehicles, IEEE ICCVE (Dec. ’13, Las Vegas, NV)
12
2. Multi‐Antenna Solutions in Vehicle Environment Contributions in vehicle environment a) Improve transmission reliability against channel impairments, such as Doppler, fading, multi‐path or interference. pp , g, p Æ Contribute to automotive/ITS applications in various radio environments. (e.g. building canyon, tunnel, mountain/hilly area) b) Increase transmission rate (~ communication capacity). b) I i i ( i i i ) b.1) Quick response to transmit large data, i.e. map, traffic, music, movies, etc. b.2) In general, the size of safety messages (for crash‐warning) is very small, but more vehicles can communicate ‐ within pre‐defined duration (e.g. critical crash warning timing) ‐ in high density areas of communication modules (e.g. freeway intersection) Æ Large safety contribution! 13
2. Multi‐Antenna Solutions in Vehicle Environment Factors affecting multi‐antenna performance g p Factors
Explanation/Impact Function of several variables including device antenna spacing, antenna polarization and multipath
MIMO channel correlation Angular spread of the Related to correlation and strongly influenced by multipath in the channel received signal Device antenna spacing Related to angular spread and correlation and orientation Antenna polarization Vertical, horizontal or circular
Noise and Interference High noise power with respect to signal power results in low SNR (signal to noise ratio)
Motion of devices or M ti fd i multipath reflectors Delay spread of reflections
Causes Doppler spread of the signal Causes Doppler spread of the signal Causes clusters of reflections to arrive at the receiver at different times different times
Reference: F. Mlinarsky, Testing MIMO Radios, “Digi‐Key” web seminar (Jan 27‐31, ’14)
14
2. Multi‐Antenna Solutions in Vehicle Environment Advantages and challenges g g Advantages
FFreedom of antenna (array) size and d f t ( ) i d shape (compared to mobile phones or laptops) + Freedom of antenna spacing and orientation i t ti + Benefit of antenna polarization + Ease of ‘Beamforming’ to target to l large vehicle antennas with long distances hi l t ith l di t + Small MIMO channel correlation
Challenges
LLarger moving speed ( i d (compared to pedestrians) + Dynamic change of channel condition ‐ Difficulty in adjusting parameters for ‘Spatial multiplexing’ ‐ Difficulty of ‘Closed‐loop’ operation ‐ Difficulty of ‘Beamforming’ to target to vehicle antennas ‐ Dynamic change of antenna orientation + Large Doppler effects
15
2. Multi‐Antenna Solutions in Vehicle Environment Multi‐antenna performance in vehicle environment p What solutions fit each automotive/ITS application? Simulation ~ Fujitsu, “Text Proposal for MIMO and Tx Diversity Comparison Section”, (TSGR1#19(01)‐0410) in TSG‐RAN Working Group meeting (Feb. ’01, Las Vegas, NV)
Flat‐fading channel (3G) Tx‐closed‐loop diversity (30km/h)
FER
(Frrame‐error‐rate)
STTD (space‐time transmit diversity) ‐ Open‐loop Closed‐loop Tx diversity
4X4 MIMO (30km/h)
2X2 MIMO (30km/h)
Eb/No (dB)
(Energy‐bit to noise ratio)
16
2. Multi‐Antenna Solutions in Vehicle Environment Multi‐antenna performance in vehicle environment p ~ T. M. Fernandez‐Carames, et al., “Performance Evaluation of Multiple‐Antenna IEEE 802.11p Transceivers Using an FPGA‐based MIMO Vehicular Channel Emulator”, EURASIP Journal on Wireless Communications and Networking 2012, 2012:215 (Jul. ’12)
FER
(Frame‐error‐ratte)
Baseline: Frequency‐flat block fading Rayleigh channel (802.11p)
Minimum mean i i square error Maximum ratio combining
Maximum-likelihood detector
Alamouti Space‐time block code block code Quasi‐orthogonal Space‐Time Block Code
SNR (dB)
(Signal noise ratio)
1X4 SIMO 4X4 MIMO
17
2. Multi‐Antenna Solutions in Vehicle Environment Multi‐antenna performance in vehicle environment p
BER
(Bit‐error‐rate)
Vehicle‐to‐road in urban canyon (802.11p)
Minimum mean square error Maximum ratio combining
Maximum-likelihood detector
Alamouti Space‐time block code Quasi‐orthogonal Space‐time block code
1X4 SIMO 4X4 MIMO
SNR (dB)
(Signal noise ratio)
18
2. Multi‐Antenna Solutions in Vehicle Environment Multi‐antenna performance in vehicle environment p
FER
(Fram me‐error‐rate)
Vehicle‐to‐vehicle on‐coming vehicle in urban canyon (802.11p)
Minimum mean square error Maximum ratio combining
Maximum-likelihood detector
Alamouti Space‐time block code Quasi‐orthogonal Space‐time block code
1X4 SIMO
4X4 MIMO
SNR (dB) ( )
(Signal noise ratio)
Deeper numerical evaluations are required.
19
3. Advanced Multi‐Antenna Solutions Multi‐User MIMO(Multiple Input Multiple Output) Forming multiple focused beams or using Tx diversity techniques to enable simultaneous communications with multiple users( ~ devices). (Typically beamforming is done by a base station or an access point.)
Æ Increase total throughput of the transmissions to multiple users by spatially distributed transmission resources. (Single User) ‐ MIMO Base Station
MU(Multi‐User) ‐ MIMO Base Station Mobile Station‐1
Mobile Station‐2
Mobile Station
Mobile Station‐3
Reference: ‐ F. Mlinarsky, Testing MIMO Radios, (“Digi‐Key” web seminar, Jan 27‐31) ‐ Y. Hara, et al., Basic Algorithm of Multi‐Antenna Technologies, Japan IEEE conference (’10)
20
3. Advanced Multi‐Antenna Solutions CoMP(Cooperative Multi‐Points) Multiple base stations cooperate to transmit to single users or multiple users. Å CoMP was was originally invented for the improvement of the reception originally invented for the improvement of the reception in cell(coverage of base station)‐edges. Joint Processing
Coordinated Scheduling
Coordinated Beamforming CSI(Channel State Information) and data exchange between each base station Coordinated transmission to the mobile station
Reference: L. Wang, Advances in Coordinated Multi‐Cell Multi‐User MIMO system, (ieee web seminar)
21
4. Next Steps Because of the time limitation, Because of the time limitation we focused on introducing various multi‐antenna solutions. Near term planning: Conduct deeper numerical analysis of multi‐antenna solutions for each automotive or ITS application for each automotive or ITS application. Æ We are planning to show our progress at the next opportunity.
Longer term planning: Propose utilizing advanced multi‐antenna solutions, Propose utilizing advanced multi‐antenna solutions for automotive or ITS applications. Æ Study advantages and challenges on how to apply them to each automotive or ITS application each automotive or ITS application. 22
Thank you for your attention!! you for your attention!! Hiro Onishi Alpine Electronics Research of America, Inc. Al i El t i R h fA i I honishi@alpine‐la.com, Tel: +1‐310‐783‐7281
Fanny Mlinarsky octoScope, Inc. [email protected], Tel: +1‐978‐376‐5841 Slide design: g Mari Hatazawa mhatazawa@alpine‐la.com 23
