Spectrum Sharing: getting there from here William Lehr MIT firstname.lastname@example.org CFP Plenary Meeting MIT October 1-2, 2014
Spectrum Sharing: outline • (1) Spectrum Working Group: intro/review • (2) Research Projects • -- Spectrum Access System: toward a new paradigm • -- Small Cell Ecosystem • -- Spectrum valuation
CFP Spectrum Working Group Website: https://people.csail.mit.edu/wlehr/SpectrumWG/SpectrumWG.htm (userid "SpectrumWG" and password "cfplsa") • Launched Nov2012. Bi-weekly calls. CFP members & invited guests. • Topics: enabling shared spectrum ecosystem • Spectrum sharing and rights (management) regimes. Policy reform. • Radio design/interference modeling, Standards, 3GPP LTE v. 802.11 • Spectrum valuation • Focus: • FCC 3.5GHz • FCC 5GHz • Other stuff: TVWS, Broadcast Incentive Auction, LTE-U, 3GPP LTE, Ofcom, ITU, WRC, and LTE-U. • White paper: “Toward more efficient spectrum management,” May 2014
FCC 3.5GHz proceeding How to design SAS? • “More spectrum for Broadband!”BB Plan (2010), Pres Memo (2010), PCAST (2012) • New Citizens Band Radio Service(CBRS), part 96 • FNPRM (April 23, 2014, GN Docket #12-354) • Commercial Sharing with Government (Incumbent DoD Radar) • Small cells (low power, 3.5GHz not great for NLOS, smaller exclusion zones) • Tiered model of usage: • (1) Incumbents: shared with Federal users (naval radar) • (2) Priority Access Licensee (PAL), like LSA/ASA, protected users • (3) General Authorized Access (GAA), like unlicensed • Spectrum Access System (SAS) and PALs • Census Block license areas, 10MHz blocks, 1 year • Aggregatable, Tradable • Seats-in-a-theater (not specific frequencies) • (Lightweight) auction if contention • Reserve minimum for GAA
Spectrum Access System: from static to dynamic Today: -- static, inflexible, uninformative Tomorrow: -- dynamic, flexible, informative -- match use opportunities w/ users -- enforcement of (changing) rights Today…. Tomorrow (??) 5
Questions for Spectrum Access (eco)System (SAS)? What functions should SAS include? (tech+users+institutions) -- Database and/or Sensing (closed loop)? -- Market making and/or Enforcement? -- How dynamic? -- Governance: role of regulator? SAS operator? -- Evolvability: how to evolve SAS? Extensibility to other bands? -- One or many SAS? (by band, by region?). Interoperability? What are rights? -- How many tiers of users? What are the sharing models? -- (going beyond primary/secondary, overlays/underlays, licensed/unlicensed) -- Granularity rights (time, geo, spectrum space)? Details: -- Interference models: worst case or more realistic? Realtime (sensors)? -- Access/security (privacy): identity management? -- Business model for SAS: how to pay for? -- etc. etc.
Spectrum Valuation: some hypotheses (*assuming transition to shared spectrum successful) Will spectrum be less scarce? -- Less artificial scarcity, but maybe more real scarcity. -- “Artificial scarcity” = NOT equal to true economic opportunity cost How will spectrum costs change? -- Entrants: lower -- Broadcasters/government: higher -- Mobile operators: lower (?) Will exclusive licensed spectrum value increase? How to measure economic value of spectrum? -- Auction values ($/MHz-POP)? M&A activity? Spectrum trading prices? -- Marginal v. Long-term (paradigm shift) valuation? -- Cost of sharing? Cost of noise? Enforcement? vs. Value excluded uses? -- Spectrum caps: how to compare high/low frequency? Exclusive/shared? -- Economic impact: Licensed more valuable than Unlicensed?
Lehr & Oliver (2014) Small Cells Ecosystem • Why “smaller cells”? • What they are, why we need them, deployment trajectories • Femtocells v. WiFi • WiFi looks like it is winning… • Market/Policy implications • Fixed-Mobile convergence: accelerator, potential industry disruption • End-user control: new vector for competition • Spectrum policy: propels drive to DSA, tilts balance toward unlicensed See: Lehr, W. and M. Oliver (2014), "Small cells and the mobile broadband ecosystem," Euro ITS2014, Brussels, June 2014, see http://econpapers.repec.org/paper/zbwitse14/101406.htm.
What are questions for Small Cell Ecosystem? WiFi (viral, single base station, unlicensed) vs. LTE (cell operators) -- Complements v. Substitutes? -- How to integrate? (at what Network Layer?) -- What spectrum? Licensed/unlicensed, or DSA? Small cell ownership/control (incentives)? -- End-users own small cell, but do they control? -- How to coordinate multiple APs? -- Is WiFi off-loading Mobile traffic or other way around? Small cells share much more than spectrum (CAPEX and OPEX) -- Backhaul: community networking? Or, operator? -- Power -- Shared antenna/base station (e.g., Network MIMO)? -- User interface/management (configuration, liability)
References • Lehr, W. and M. Oliver (2014), "Small cells and the mobile broadband ecosystem," Euro ITS2014, Brussels, June 2014, available at http://econpapers.repec.org/paper/zbwitse14/101406.htm. • Lehr, W. (2014), “PALs as Options to Exclude GAA,” Reply Comments submitted in the matter of Amendment of the Commission's Rules with Regard to Commercial Operations in the 3550-3650 MHz Band, GN Docket 12-354, August 15, 2014, available at http://apps.fcc.gov/ecfs/document/view?id=7521763142. • Lehr, W. (chair) (2014) “Toward More Efficient Spectrum Management: New Models for Protected Shared Access,” a White Paper prepared by the MIT Communications Futures Program Spectrum Working Group, submitted to FCC’s 3.5GHz proceeding (Docket #12-354), available at http://apps.fcc.gov/ecfs/comment/confirm?confirmation=201437236301. • Chapin, John and William Lehr (2011), "Mobile Broadband Growth, Spectrum Scarcity, and Sustainable Competition," TPRC 2011, Alexandria Virginia, September 2011, available at SSRN: http://ssrn.com/abstract=1992423.
Slides Not Used Background
ASA/LSA/PA/GAA -- 3.5 US -- 2.3 EU March 2014
User/Use … Interference Protection Needed Weak Strong Transaction Costs (to acquire rights relative to value) High Unlicensed C&C, subsidized licensed Low Licensed/Unlicensed ?? Licensed Market success: More congestion Fast innovation Smart radio systems: Greater interference robustness More sharing options Spectrum scarcity is matter of perspective • Off-diagonal cases more common? Weak/low or Strong/high • Dynamic shared spectrum options • Multiple, complementary regulatory options
Small Cells and the Mobile Broadband Ecosystem(or, Small cells: Femtocells v. WiFior, Off-loading Mobile Traffic: Femtocells v. WiFi) Miquel Oliver UPF William Lehr MIT ANA Group Presentation May 8, 2014
Outline • Why “smaller cells”? • What they are, why we need them, deployment trajectories • Femtocells v. WiFi • WiFi looks like it is winning… • Market/Policy implications • Fixed-Mobile convergence: accelerator, potential industry disruption • End-user control: new vector for competition • Spectrum policy: propels drive to DSA, tilts balance toward unlicensed
“Small Cells” Cellular legacy… expand coverage, capacity mobile cellular 2G/3G/4G e.g., Femto forum becomes SmallCellForum in Feb 2012 WiFi – a 802.11a/b WLAN, originally for wireless Ethernet up to 100m • Small Cells • Limited Range (~100m) • Variable data rates (10-100Mbps+, faster than current cellular) • Low power (20-100mW)
Why smaller cells? • Spectrum scarcity : spatial reuse • Split cells and 2x the number of users • Bigger hand-off problem for mobility • Coverage & Capacity hot spots • Coverage: in-home dead-zones, rural extension • Capacity: high-traffic areas, incremental additions • Power conservation • Power/range related (especially for omni-directional) • More resource intense services, more power is a concern • Safety? (Miquel says no…) • Market evolution/Technical progress • Demand growth everywhere/always connected, rich services… • Technology faster, smaller, cheaper; hetnets; convergence of WiFi/LTE functionality… • Strategic & policy…
Femtocells v. WiFi WiFi winning today…scale/installed base/cost advantages compelling… • But…. • LTE-U : why can’t LTE match cost-economies of WiFi? Maybe just software… • NextGen Wi-Fi : (Hotspot 2.0, etc.). Xfinity modems with dual WiFi. Etc. • NextGen wireless may be something else altogether
Small cell future? Backhaul? • Fixed BB, yes. But how managed? Usually end-user. • Could this be over IP, but NOT Internet BB? AP owner/management? • Owner (CAPEX, OPEX): end-user typically in home/local; operator wide-area • Management: typically, end-user (WiFi), operator (femto) Spectrum? • Licensed/unlicensed or something new? Deployment/Market Scenarios
Fixed-Mobile Convergence Accelerator! • Drives need to integrate networks, enables platform competition • Mobile & fixed BB have differentiated, complementary features. • Platform competition: Fixed v. Mobile, WiFi v. 3G/4G? • Coverage, capacity Demand : fixed/mobile complements… • and demand price substitutes (low-end market drive fixed/mobile differentiation) • but potential for supply substitution: demand cream-skimming/investment crowding out “dirt road” risk • Small cells wired backhaul (FTTx driver) • Fixed BB providers own the wires • (Community networking: mesh/wireless backhaul feasible) • Mobility: nomadic (slow hand-off) v. fast? Tail of the dog: Cellular off-loads to WiFi or WiFi off-loads to cellular? (allocation of shared costs…) • Interconnection: Fixed/Mobile operators • Who owns the customer? How are back-haul costs recovered? • Is off-load traffic OTT or separate service? New ISP peering model?
End-user control • Wireless: new vector for value creation, facilities competition • APs: end-user controlled • Backhaul/roaming: community (municipal networking) • IoT and lots of stuff that is (can be) mostly “local” • Benefits? • Uncork last-mile bottleneck: response to NN concerns… • End-user autonomy/freedom: choice, “have it your way” • Edge-based innovation: decoupled, local, viral, “let a 1000 flowers bloom” • Problems? • Source-based routing: unbundle ISP offers/optimization? • End-to-end QoS/Reliability: fault assessment? • Coordination? Local assets easier with small cells, roaming harder… • Interoperability, Connectivity suffer? • Open standards (WiFi and LTE) as a response.
Spectrum policy • Small cells could operate in either, but balance tilted toward unlicensed (?) • WiFi wins, fills sails of unlicensed… • Small cells local (weaker justification for wide-area exclusivity) • Shift to DSA makes spectrum coordination more granular/local • Spectrum smaller share of total value per AP for small cell (siting, install, power, etc.
Spectrum policy: future is shared spectrum! • Lots of ways to share: Frequency/Geo/time/code/angle/beam-forming… etc. • Coordinated/Uncoordinated: licensee (band manager), contract, protocol • Licensed/unlicensed: end points on continuum interference protection rights • All are property rights, all have imperfect (costly) interference protection • Legal rights only have relevance in context of larger ecosystem • Goal: more granular/dynamic/local resource management • Dynamic Spectrum Access (DSA): smart radios share in all ways • Share across users/uses (LTE already), and NETWORKS • More commercial spectrum for mobile BB: licensed, unlicensed and new regimes (TVWS, 3.5GHz, 5GHz, etc.) • Flexible/adaptive: future-proof regulatory process
Spectrum Policy: paradigm shift… • DSA : more granular spectrum management • White space: identify additional sharing opportunities • Better able to provision for on-demand needs (bursty wireless) • Frequency (waveform) agile radios: seat in theater, not specific seat.. • Interference protection: expanded rights tiering • Harmful interference: rights assignment, improved propagation models • Rx standards: protection tied to Rx quality (Lightsquared issue) • Spectrum Access System (SAS) • Mechanism for coordinating access by band/geo/time • Integrating/coordinating regulatory policy/markets/technology • Static (one-time dbase, open loop) Real-time (sensing also, closed loop) • e.g., TVWS, 3.5GHz (small cells), 5GHz • Q: Who owns/manages SAS? How dynamic? (Role for sensing?) • Q: SAS access privileges? (security/privacy concerns: IDENTITY MGMT!) • Q: SAS innovation? “Race to the top” interoperability…
Small cells and broadband/mobile costs • “$1/GB for mobile, $0.10/GB for fixed … 10x difference” • What costs included? • Marginal costs: spectrum, power, (externalities – congestion) • Incemental (fixed) costs: infrastructure, (spectrum) • CPE, Backhaul, Interconnection (peer/transit) • Fixed: Modem/DSLAM; Mobile: Handset/Base station • Last-mile – fixed (dedicated, ROW), mobile (shared) • Life of capital (economic life): legacy plant? • Why? (assume estimates true…) and how changing? • Spectrum scarcity but much less for high frequency, LOS • Congestion growth makes worse, but DSA eases • Backhaul, Handset CAPEX/OPEX shifted from mobile to user/fixed • Maturity/Cost Fixed mature/mobile new (Moore’s law still working) • Comparison flawed • Subsidies: legacy, USF favors fixed. Either/both too high/low. • Missing costs with fixed • Capacity is for peak data rate ($/Gbps), $/GB makes no sense
DSA: lots of radio tech to expand apps/capacity Source: http://groups.winnforum.org/d/do/3839
SAS: a more dynamic model (UK version) … Source: http://www.unwiredinsight.com/2013/tv-white-space
TVWS Database • Integrate information from multiple sources: rules by band, registration, physical terrain, technical parameters, etc. • Rules differ by jurisdiction, location, time, user, etc.
Real-time spectrum usage -- Over time, by band, by use -- History & current -- Coverage? * Open source code * Looking for partners… -- Part of the SAS???
Microsoft Spectrum Observatory (May 2014) : 11 sites live -- CSAIL -- Antenna: 50MHz-4.4GHz -- Live since April 2014 Power spectral density -- -20/-180 dB/Hz -- 5/7/2014, 12am snap shot
Microsoft Spectrum Observatory – Average Power Density (Cambridge, May 2014)
Small Cell Options • Equipment makers have full spectrum of solutions for cellular and WiFi small cells, indoor/outdoor applications • E.g., Alcatel-Lucent – slides presented at FCC 3.5Ghz Workshop (Jan2014)
User/Use … Interference Protection Needed Weak Strong Transaction Costs (relative to value) High Unlicensed C&C, subsidized licensed Low Licensed/Unlicensed ?? Licensed Market success: More congestion Fast innovation Smart radio systems: Greater interference robustness More sharing options Spectrum scarcity is matter of perspective • Off-diagonal cases more common? Weak/low or Strong/high • Dynamic shared spectrum options • Multiple, complementary regulatory options
Future is shared spectrumdecoupling of spectrum frequencies from applications (& infrastructure)
Spectrum Management and DSA • Agenda: future is shared spectrum. Need commercialize DSA tech, business models and policy to support novel ways to share spectrum. • PCAST report: government spectrum sharing • (http://www.whitehouse.gov/sites/default/files/microsites/ostp/pcast_spectrum_report_final_july_20_2012.pdf) • WSRD planning : research agenda • (https://connect.nitrd.gov/nitrdgroups/index.php?title=Wireless_Spectrum_Research_and_Development_(WSRD)#title) • Wireless@MIT : technologies to enable 1000+ fold efficiency • (http://wireless.csail.mit.edu/) • NSN-MIT LSA/ASA CFP Spectrum WG • Other stuff… • Public safety (FirstNet, 700MHz, testbeds…) • TVWS • Small Cells (DAS sharing, network MIMO, shared infrastructure)
Spectrum/Wireless related research… • Weiss, M., W. Lehr, L. Cui, and M. Altamini (2012), "Enforcement in Dynamic Spectrum Access Systems," TPRC2012, Alexandria, VA, September 2012 • Lehr,W. and R. Yates (2012), "MobilityFirst, LTE and the Evolution of Mobile Networks," IEEE DySPAN2012, Bellevue, Washington, October 2012 • Weiss, M., W. Lehr, and S. Delaere (2010), "Sensing as a Service: An Exploration into Practical Implementations of DSA," Proceedings of IEEE DySPAN2010, Singapore • Chapin, J. and W. Lehr (2011) "Mobile Broadband Growth, Spectrum Scarcity, and Sustainable Competition," 39th Research Conference on Communications, Information and Internet Policy (www.tprcweb.com), Alexandria, VA, September 2011. • Lehr, W. and J. Chapin (2010), "On the convergence of wired and wireless access network architectures," Internet Economics and Policy, 22 (2010) 33-41. • Chapin, J. and W. Lehr (2010) "SCADA for the Rest of Us: Unlicensed Bands Supporting Long-Range Communications," paper prepared for the 38th Research Conference on Communication, Information and Internet Policy (www.tprcweb.com), Alexandria, VA, October 1-2, 2010. • Lehr, W. and N. Jesuale (2008), “Spectrum Pooling for Next Generation Public Safety Radio Systems,” Proceedings of the IEEE Dynamic Spectrum Access Networks (DySPAN08) Conference, Chicago, October 14-17, 2008. • Chapin, J. and W. Lehr (2007), "The path to market success for dynamic spectrum access technologies," IEEE Communications Magazine, May 2007 (pdf=http://people.csail.mit.edu/wlehr/Lehr-Papers_files/chapin_lehr_IEEE_communications_submitted.pdf) • Chapin, J. and W. Lehr (2007), "Time-limited Leases for Innovative Radios," with John Chapin, IEEE Communications Magazine, June 2007. • Lehr, W., M. Sirbu, and S. Gillett (2006), "Wireless is Changing the Policy Calculus for Municipal Broadband," Government Information Quarterly, 23 (2006) 435-453
FCC 5GHz Proceeding • Revision of Part 15 rules for U-NII Devices in the 5 GHz Band • ET Docket No. 13-49, released April 1, 2014. • Impacts virtually entire 5Ghz band (~600MHz for unlicensed use). • 5Ghz (802.11a) v. 2.4GHz (802.11b): reduced coverage, less congested • Since 1997, but carve outs for satellite/government (radar) users, now to be shared… • Significantly enhances attractiveness of 100MHz • Higher power limits for indoor (802.11ac!). • Still higher for Point-to-Point (backhaul) use (WISPs) • 5GHz potential • Expands Wi-Fi (commodity) hardware option • Unlicensed access • Bigger bands (better performance) (e.g., vs. LTE…)
FCC 3.5GHz proceeding • New Citizens Band Radio Service(CBRS), part 96 • FNPRM (April 23, 2014, GN Docket #12-354) • Small cells • (but also, rural and other sharing models) • 3.5Ghz not great for LOS, cannot be cleared of Federal incumbents • High-power sharing (e.g., WiMAX) leaves too little for sharing • Tiered model of usage: • Incumbents: shared with Federal users (naval radar) • Priority Access Licensee (PAL), like LSA/ASA • General Authorized Access (GAA), like unlicensed • SAS and PALs • Census Block license areas, 10MHz blocks, 1 year • Aggregatable, Tradable • Seats-in-a-theater (not specific frequencies) • (Lightweight) auction if contention • Reserve minimum for GAA
Other FCC proceedings • 600 MHz incentive band auction • AWS-3 spectrum auction • (and lots more….)
Small Cells and the Future of Mobile Broadband • Vision of the Mobile BB Future • Implications for Spectrum Management • Why Small Cells are part of this? • Issues/challenges • LTE/WiFi • End-user control • Spectrum management
Mobile Broadband Future (a vision…) • Pervasive computing always/everywhere connected • (Internet) Cloud computing/storage in-network, fat/thin clients • IoT (M2M) sensing/real-time decision-making, on-demand video • FTTx lots of dense neighborhood fiber • Mobility all dimensions/scales… geo, time, context (network) • Wireless everywhere everyone wants more Spectrum! • All uses: communication & sensing • All users: Feds & commercial, planned & ad hoc • All kinds: long/short range, high/low power, new/legacy