Lucent Technologies Bell Labs Innovations New and Emerging

Lucent Technologies Bell Labs Innovations New and Emerging Wireless Technologies Beyond 3 G Samuel Lucent Technologies Swindon UK L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations TOC • Economics and Vision • Background to the Problem • Future and Emerging Technologies – – – MIMO OFDM Beam forming – IA and Antenna Array Interference cancellation Network Time Scheduling • IEEE Approaches • Summary L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Wireless Experience Curve: 1985 to 1996 Cost per Minute $10 CEO’s Real Estate Agents 1985 1986 Replace Calling 1987 1988 Cards 1989 $1 Elasticity ~ 3 $0. 1 Note: DRAM and airtime both reduced ~10 x from 1985 -1995 1990 1991 1992 1993 1994 1995 1996 Intercom Def of Elasticity: %change in X/% change in y Source: G. Blonder, AT&T Labs, 1977 Note: Cost excludes marketing and sales expense and are in 1996 dollars 1 10 1000 Cumulative Minutes (B) 10000 • Next generation systems must be spectrally efficient across the network (bandwidth where needed). • Equipment providers will provide the “compilers” for application creation. • Partnering will be the norm. L. Samuel Lucent Technologies - Proprietary (RESTRICTED) 3

Lucent Technologies Bell Labs Innovations Economics and Visions L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Information Anywhere Vision: Lucent Technologies Example project – EU 6 FP Ambient Networks Bell Labs Innovations Ambient Networks: - Common Control Services - Dynamic Network Composition Services Ambient Control Space Ambient Connectivity Corporate Person al PAN L. Samuel Fixed WLAN 3 G 4 G 2. 5 G Community Home Vehicular VAN CAN HAN Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Background to the problem Motivation L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Preceived The wireless channel Bell Labs Innovations delay spread • Scattering causes local signal fading • Delay spread dependent on environment (small for indoor, large for macrocell) L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Pr Pr Channel Normal-modes Bell Labs Innovations delay spread t • Classic static multipath channel is linear. • Normal modes are simple sinusoids. OFDM then is optimal in this sense. • Information is broken into small frequency bands with flat fading. Great for MIMO type applications. • Active research areas within Bell Labs: – OFDM, chirped pulses, MC-CDMA, OFDM-CDMA for legacy and practical implementation L. Samuel Lucent Technologies - Proprietary (RESTRICTED) f

Lucent Technologies Increasing the Data Rate in CDMA Original signal Multipath channel Rake Receiver Bell Labs Innovations Rx signal time diversity ideal bit rate multiple access noise floor bit rate goes to zero at infinite bandwidth and fixed power UMTS L. Samuel bandwidth Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Live Wireless Transaction Measurements 1600 Latency Packet Size 1200 800 400 0 5 10 15 20 25 Traffic characteristics: • Initial download of HTTP skeleton resulted in GET of large objects. Many 1500 packets retrieved. • Period 9 - 20 consumed by DNS accesses to resolve www. xxx. com addresses to IP addresses. • End of transaction resulted in many small object retrievals. Large uplink payloads for smaller downlink payloads. • Latency chart illustrates queuing within system as generated load piles up in uplink and downlink directions. • This traffic profile is typical of Web accesses. 5 10 sec 20 Netscape Browser access to www. adobe. com: • blue dots are downlink packets, red dots are uplink packets. • average downlink Kbps to 1 second peak = 4. 3: 1 • average uplink Kbps to 1 second peak = 4. 7: 1 • MRU was 1500 bytes • TCP Window Size was 8, 192 bytes We cannot ignore delay – TTI Issues We cannot ignore uplink – Symmetry Issues L. Samuel 25 Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations General Throughput Equation • To optimize data performance we should combine rate and power control • OFDM is convenient for water filling • Keep number of sub-carriers manageable for uplink channel information L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Future and Emerging Technologies L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations MIMO L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Space: The Last Frontier Bell Labs Innovations q Convergence of ubiquitous wireless access and broadband internet creates insatiable demand for high bit rate wireless access q System capacity is interference limited - cannot be increased by increasing transmitted power q The spectrum has become a scarce and very expensive resource q For Cellular systems reducing cell size is not viable q Increasing spectral efficiency with multiple transmit and multiple receive antennas opens a new dimension, space, offering exceedingly high bit rates without increasing transmitted power bandwidth allocation L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Bandwidth Efficiency Limits C. Shannon Bell Labs Technical Journal, 1950 L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Efficiency Limits with a Single Array Adding a single array does provide diversity against fading, but it does not change the (slow growth) logarithmic nature of the bandwidth efficiency limit . . . Rx. M L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Lifting the Limits with Dual Arrays s 1 s 2 . . . s. M Rx. M number of antennas in the smaller of the transmit and receive arrays L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Predicted outage capacities SPECTRAL EFFICIENCY (bps/Hz) 150 SPECTRAL EFFICIENCY vs. NUMBER ANTENNAS AT 1% OUTAGE 24 d. B 18 d. B 100 12 d. B 6 d. B 1 N Optimum Combining at 24 d. B 50 0 d. B 0 8 10 20 30 40 50 NUMBER OF UNCORRELATED ANTENNAS (M=N) L. Samuel Lucent Technologies - Proprietary (RESTRICTED) 60

Lucent Technologies Bell Labs Innovations MIMO Capacity Increases C/W=log 2(det(I+r. HHH)) ~N*log 2(1+SNR) Capacity grows as the number of antennas! Receiver Chip (2. 1 mmx 1. 9 mm) • Increases the spectral efficiency • Compact antenna arrays • Low-cost receivers L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies MIMO Bell Labs Innovations MIMO: Increase data rates by exploiting multiple antennas at both Tx and Rx. Tx User data is encoded, modulated and transmitted simultaneously over multiple antennas High Data Rates L. Samuel Channel Rx High levels of interference at the mobile requires sophisticated yet efficient signal processing. Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations The Wireless Channel in MIMO Processing Multiple antenna techniques rely on the characteristics of the spatial signature: • Diversity techniques rely on the assumption that distinct spatial signatures correspond to different pairs of transmit-receive antennas. • Intelligent antenna techniques rely on the efficient adaptation of the array pattern according to the spatial distribution of the desirable user and interferers. L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Open-Loop Transmit Diversity • Time-Switched Transmit Diversity (TSTD) x 1 Data Mobile time x 1 , x 2 time • Space-Time Block Code Transmit Diversity (STC) Data x 1 , x 2 Space-Time Block Code x 1 x 2 time –x 2* x 1* L. Samuel time Lucent Technologies - Proprietary (RESTRICTED) Mobile

Lucent Technologies MIMO Research Trends Bell Labs Innovations Advanced MIMO receivers can be costly on the downlink due to limitations in mobile form-factor and complexity. • • L. Samuel High-performance, low-complexity detection algorithms for MIMO. Algorithms based on joint-detection or serial/parallel interference cancellation techniques following space-time equalization. High-performance, low-complexity receiver architectures for MIMO based on multiple iterations between a low-complexity detector and a error-correcting decoder. Transmitter encoding for High-Order Modulations in MIMO, allowing reduced complexity at the receiver. Dynamic packet scheduling across multiple antennas. Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Propagation Modeling & Measurements Indoor propagation measurements consistently show high BLAST gains. Recent outdoor measurements demonstrate similar results. Laptop 120 ft BLAST/1 x 1 capacity Mobile Measurements theory omni antenna in laptop time (sec) • narrowband channel capacity in mobile suburban 80% of theory • narrowband channel capacity of laptop in van is 65% of theory • Capacity improvements are real L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations OFDM L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Orthogonal Frequency Division Duplexing IFFT N Block 1/NT sin(wt) cos(wt) f • • Breaks high-speed data into low-rate parallel streams Longer symbol period reduces ISI & ICI for spread OFDM fn=fc+n. Df, where for orthogonality Df. Ts=1 Simple DFT implementation L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Beam Forming – Intelligent Antenna L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Performance Enhancements Transmit Diversity achieves: • Improved call quality on the downlink by combating multipath fading. • Reduced BTS transmit power, thereby reducing downlink inter -cell interference. Intelligent Antennas achieve: • Higher antenna gain - by maximising received energy or transmitting more effective power. • Reduction of Interference by maximising Signal – to Interference Ratio L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Intelligent Antennas Lucent Technologies Bell Labs Innovations • An antenna-array transceiver system. • Combined with a base station architecture and signal processing techniques designed to dynamically select or form the “optimum” beam pattern per user. Omnidirectional Cell Site L. Samuel Three Sector Cell Site Lucent Technologies - Proprietary (RESTRICTED) Intelligent Antenna Cell Site

Lucent Technologies Bell Labs Innovations Adaptive Antenna Principle Conventional Receiver Adaptive Antenna Mobile 1: Direct Ray Mobile 1: Reflected Ray Mobile 2 Interferer Mobile 2: Direct Ray Mobile 1: Reflected Ray Antenna spatial gain patterns are fixed. L. Samuel Mobile 2: Direct Ray Mobile 1: Reflected Ray Adaptively “weight” and combine multiple antenna signals to optimise performance. Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Closed-Loop Transmit Diversity w Data Mobile 1 w 2 Closed-loop Tx. AA Feedback on Uplink Quantised Weights • Weights are computed by the mobile as a function of the downlink channel estimates to maximise the received signal energy. • Weights are then quantised in amplitude/phase and sent back on the uplink control channel. L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Pathloss (d. B) Multi-Antenna Solutions d. B antenna separation time Signal fades in time and space. Include both space and time diversity L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Base and terminal Smart Antenna Prototypes L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Basestation Antenna Configurations polarization beams • two beam lobes • polarization and spacial diversity configurations • 2 -6 d. B improvement • high gain for low-speed users • 4 -fold diversity on the uplink • 16 element tower top electronics • 9 o beamwidth with -35 d. B side lobes • Space-division multiple access L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Polarization Antennas at Mobile Bell Labs Innovations H E Without scattering polarization Tripole antenna perpendicular to k-vector Three omni-antennas co-located at feed point Key feature to obtain MIMO gains: • achieving the separation between Antennas on the end device Ceramic Antenna, Tripole Antenna L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Interference Cancellation L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Interference Mitigation (1): Cellular Downlink Bell Labs Innovations Intra- and inter-cell interference mitigation algorithms at the mobile. Serving Node. B Interfering Node. B (1 -Antenna Tx) K 1 Codes Inter-cell Interference K 2 Codes Multi-Antenna UE • L. Samuel Iterative detectors based on space-time filtering. Filter weights trained via transmitted pilots of the desired signal using Least squares and semi-blind (e. g. constant modulus) optimisation criteria. Lucent Technologies - Proprietary (RESTRICTED)

Interference Mitigation (2): WLAN Lucent Technologies Bell Labs Innovations Inter-system Interference due to co-existing technologies in unlicensed bands. • L. Samuel Space-time filtering at the receiver in conjunction with enhanced MAC algorithms to cope with inter-system interference. Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Interference Mitigation Advances Bell Labs Innovations K=4, M=2, Nt=20, Nd=80, SIR=0 d. B, 500 trials 0 10 MSE Known parameters LR with outliers selection LS LSB SB (delta=0. 1) -1 Conventional solutions Proposed semi-blind solution 10 Finite data ML benchmark -2 10 10 11 12 13 14 15 16 SNR, d. B 17 18 19 Techniques advancing to point where they approaching theoretical limits L. Samuel Lucent Technologies - Proprietary (RESTRICTED) 20 Optimal solution: Full a priori info

Lucent Technologies Bell Labs Innovations Network Time Scheduling L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Short Delay vs. Long Delay Services link loss Bell Labs Innovations Tx power Delay constraints force user to power control through fades delay jitter link loss Tx power Schedule transmission around fades. Transmit at full power maximum rate. Higher latency. L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Data scheduling high latency low latency Partition low and high latency services in power L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Coordinated Cell Scheduling MESH Network • 802. 16 a • Other relay techniques being proposed in 4 G research possible 3 X • Considered a key improvement Future Emerging Technology by EU • High priority packets are sent with neighbors quiet. • Coordination is local between nearest neighbour L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations IEEE Approaches L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Impact of 802. 20, 802. 16 , 802. 11 IEEE approach is largely OFDM based • Even IEEE 802. 15. 3 is OFDM based Actively adding mobility to the standards: • 802. 16 e and 802. 20 • 802. 11 considering management plane that would allow mobility Differences: • 802. 20 – wide scale mobility (vehicular) – frequency band 500 Mhz to 3. 5 GHz • 802. 16 e – pedestrian – Based on 802. 16 a frequency band 2 GHz to 6 GHz Appears there is an overlap between two L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Efficiency Targets for 802. 20 Source IEEE 802. 20 L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations 802. 11: Indoor Wireless LAN Migration First Generation Wireless LANs A A · Peer/Peer and Client/Server · Small User Population · Isolated "Cells" and User Groups · Non-Contiguous Coverage · Indoor Operation · Limited Mobility · Mostly Asynchronous Traffic · Slower than Ethernet IEEE 802. 11 Fourth-Generation of Wireless Communications · Larger User Population · Managed Services · Full Roaming/Handoff Capability · Contiguous Coverage in Dense Areas · Wider Area Coverage for Community LANs · Mobility (Follow-Me Service) · Mix of Async and Isochronous Traffic · Higher System Utilization · Enhanced Security Second-Generation Wireless LANs · Inter. Net/Intra. Net · Ethernet-Compatible Speeds · Multiple RF Bands to operate Third-Generation Wireless Communications • TDMA • EDGE • Wideband CDMA Merge of 3 G and 4 G services (WLAN & WAN) Source ATT proposal to IEEE 802. 11 L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations 802. 11: Device Management Process of Managed 802. 11 devices in the Standards (Small steps to make good progress) Inter-Access Port Protocol Radio Resource Measurements Remote Managed Device Inter-Communications between APs (Now a Standard) Ability to obtain MAC and PHY measurements by Upper Layers (Now a Task Group) Enable external entities to manage Devices (APs and Clients) (Proposed Next Logical Step) Source ATT proposal to IEEE 802. 11 L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations IEEE impact on 4 G Mobility: Higher layer approach to mobility: • MIP and enhancements e. g. Dynamic Home Agents • Considering proposals to Link layer mobility • That all 802. xx standards adhere to MAC and VLAN bridging Conclusion: Aim is for improved spectral efficiency Incorporating ideas of: • PAN - 802. 15. x • VAN – 802. 20, 802. 16 e • HAN – 802. 11(a-g) • CAN – 802. 16 a Potential High Impact on 4 G L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations Summary L. Samuel Lucent Technologies - Proprietary (RESTRICTED)

Lucent Technologies Bell Labs Innovations In this talk we have • Looked at the motivation and vision for the emergence of new technologies • Looked at which technologies are likely to succeed • Noticed that the IEEE approach to 4 G standardisation may succeed before others Thank You!! L. Samuel Lucent Technologies - Proprietary (RESTRICTED)