BR112016023760B1 - SYSTEMS AND METHODS FOR CONCOMITANT USE OF SPECTRUM WITHIN THE ACTIVELY USED SPECTRUM - Google Patents

Abstract

SYSTEMS AND METHODS FOR CONCOMITANT USE OF SPECTRUM WITHIN THE ACTIVELY USED SPECTRUM. Systems and methods are described for simultaneous use of actively used spectrum for new TDD or FDD networks, and also to allow the use of distributed input and distributed output (DIDO) techniques with both new networks and existing networks. existing networks in the same spectrum.

Description

REFERENCE TO RELATED ORDERS

[0001] This application claims the benefit of and priority over co-pending US provisional patent application No. 61/980,479, filed on April 16, 2014, entitled "Systems And Methods For Concurrent Spectrum Usage Within Actively Used Spectrum".

[0002] This application may be related to the following US patent applications and provisional US patent applications:

[0003] U.S. Provisional Application Serial No. 61/937,273, entitled "Systems and Methods for Mapping Virtual Radio Instances into Physical Areas to Coherence in Distributed Antenna Wireless Systems";

[0004] US Application Serial No. 13/844,355, entitled "Systems and Methods for Radio Frequency Calibration Exploiting Channel Reciprocity in Distributed Input Distributed Output Wireless Communications";

[0005] US Application Serial No. 13/797,984, entitled "Systems and Methods for Exploiting Inter-cell Multiplexing Gain in Wireless Cellular Systems Via Distributed Input Distributed Output Technology";

[0006] US Application Serial No. 13/797,971, entitled "Systems and Methods for Exploiting Inter-cell Multiplexing Gain in Wireless Cellular Systems Via Distributed Input Distributed Output Technology";

[0007] US Application Serial No. 13/797,950, entitled "Systems and Methods for Exploiting Inter-cell Multiplexing Gain in Wireless Cellular Systems Via Distributed Input Distributed Output Technology";

[0008] US Application Serial No. 14/156,254, entitled "System and Method For Distributed Antenna Wireless Communications";

[0009] US Application Serial No. 14/086,700, entitled "Systems and Methods for Exploiting Inter-cell Multiplexing Gain in Wireless Cellular Systems Via Distributed Input Distributed Output Technology";

[0010] US Application Serial No. 14/023,302, entitled "Systems And Methods To Coordinate Transmissions In Distributed Wireless Systems Via User Clustering";

[0011] US Application Serial No. 3/633,702, entitled "Systems and Methods for Wireless Backhaul in Distributed-Input Distributed-Output Wireless Systems";

[0012] US Application Serial No. 13/475,598, entitled "Systems and Methods to enhance spatial diversity in distributed-input distributed-output wireless systems";

[0013] US Application Serial No. 13/464,648, entitled "System and Methods to Compensate for Doppler Effects in Distributed-Input Distributed Output Systems";

[0014] US Application Serial No. 13/461,682, entitled "System and Method for Adjusting DIDO Interference Cancellation Based On Signal Strength Measurements";

[0015] US Application Serial No. 13/233,006, entitled "System and Methods for planned evolution and obsolescence of multiuser spectrum";

[0016] US Application Serial No. 13/23,996, entitled "Systems and Methods to Exploit Areas of Coherence in Wireless Systems";

[0017] US Application Serial No. 12/802,989, entitled "System And Method For Managing Handoff Of A Client Between Different Distributed-Input-Distributed-Output (DIDO) Networks Based On Detected Velocity Of The Client";

[0018] US Application Serial No. 12/802,988, entitled "Interference Management, Handoff, Power Control And Link Adaptation In Distributed-Input Distributed-Output (DIDO) Communication Systems";

[0019] US Application Serial No. 12/802,975, entitled "System And Method For Link adaptation In DIDO Multicarrier Systems";

[0020] US Application Serial No. 12/802,974, entitled "System And Method For Managing Inter-Cluster Handoff Of Clients Which Traverse Multiple DIDO Clusters";

[0021] US Application Serial No. 12/802,958, entitled "System And Method For Power Control And Antenna Grouping In A Distributed-Input-Distributed-Output (DIDO) Network";

[0022] US Patent No. 8,654,815, granted on February 18, 2014, entitled "System and Method for Distributed Input Distributed Output Wireless Communications";

[0023] US Patent No. 8,571,086, granted on October 29, 2013, entitled "System and Method for DIDO Precoding Interpolation in Multicarrier Systems";

[0024] US Patent No. 8,542,763, granted on September 24, 2013, entitled "Systems And Methods To Coordinate Transmissions In Distributed Wireless Systems Via User Clustering";

[0025] US Patent No. 8,428,162, granted on April 23, 2013, entitled "System and Method for Distributed Input Distributed Output Wireless Communications";

[0026] US Patent No. 8,170,081 granted on May 1, 2012, entitled "System And Method For Adjusting DIDO Interference Cancellation Based On Signal Strength Measurements";

[0027] US Patent No. 8,160,121, granted on April 17, 2012, entitled "System and Method For Distributed Input-Distributed Output Wireless Communications";

[0028] US Patent No. 7,885,354, granted on February 8, 2011, entitled "System and Method For Enhancing Near Vertical Incidence Skywave ("NVIS") Communication Using Space-Time Coding";

[0029] US Patent No. 7,711,030, granted on May 4, 2010, entitled "System and Method For Spatial-Multiplexed Tropospheric Scatter Communications";

[0030] US Patent No. 7,636,381, granted on December 22, 2009, entitled "System and Method for Distributed Input Distributed Output Wireless Communication";

[0031] US Patent No. 7,633,994, granted on December 15, 2009, entitled "System and Method for Distributed Input Distributed Output Wireless Communication";

[0032] US Patent No. 7,599,420, granted on October 6, 2009, entitled "System and Method for Distributed Input Distributed Output Wireless Communication";

[0033] US Patent No. 7,418,053, granted on August 26, 2008, entitled "System and Method for Distributed Input Distributed Output Wireless Communication";

Background of the invention

[0034] Both Frequency Division Duplex (FDD) mode and Time Division Duplex (TDD) mode are commonly used in wireless communication systems. For example, the LTE standard supports both FDD mode and TDD mode, and as another example versions of the 802.11 standard (e.g., Wi-Fi) support the TDD mode of operation.

[0035] In the case of LTE, several numbered bands are defined within what is called the Evolved UMTS Terrestrial Radio Access (E-UTRA) air interface. Each E-UTRA band not only specifies a specific band number, it defines whether the band is intended for FDD or TDD, and which bandwidths are supported within the band (see, for example, http://en.wikipedia. org/wiki/LTE_frequency_bands#Frequency_bands_and_c hannel_bandwidths for a list of E-UTRA bands and their specifications). For example, Band 7 is an FDD band defined as using the frequency ranges 2500 to 2570 MHz for uplink (UL), 2620 to 2690 for downlink (DL), and which supports signal bandwidths of 5, 10, 15 and 20 MHz within each of the UL and DL bands.

[0036] In many cases, the E-UTRA bands overlap. For example, different bands may be common spectrum that has been allocated to different markets or regions. For example, Band 41 is a TDD band that uses the 2496 to 2690 MHz frequency bands for both UL and DL, which overlaps both the UL and DL bands in FDD Band 7. Currently, Band 41 is used in the US by Sprint, while Band 7 is used by Rogers Wireless in neighboring Canada. Thus, in the USA, the range from 2,500 to 2,570 MHz is TDD spectrum, while in Canada this same frequency range is UL for FDD spectrum.

[0037] Typically, a mobile device, when connecting to a wireless network, will scan the band for transmissions originating from one or more base stations, and typically during the connection procedure, the base station will transmit network characteristics, such as the bandwidth used by the network, and details of the protocol in use. For example, if an LTE device scans the 2620 to 2690 MHz band in the US, it may receive an LTE DL frame transmitted by an eNodeB that identifies the spectrum as Band 41, and if the LTE device supports Band 41 and TDD , it can try to connect to the eNodeB in TDD mode on that band. Similarly, if an LTE device scans the 2620 to 2690 MHz band in Canada, it can receive an LTE DL frame transmitted by an eNodeB that identifies the spectrum as Band 7, and if the LTE device supports Band 7 and FDD, it can try to connect to the eNodeB in FDD mode on Band 7.

[0038] Most previous LTE networks deployed worldwide used FDD mode (e.g., Verizon, AT&T), but TDD mode is increasingly being used, both in markets with extensive FDD coverage, such as the US (where Sprint is installing TDD) as well as in markets that do not yet have extensive LTE coverage, such as China (where China Mobile is installing TDD). In many cases, a single carrier is deploying both FDD and TDD on different frequencies (for example, Sprint operates both FDD LTE and TDD LTE on different frequencies in the US), and may offer LTE devices that can operate in both modes. , depending on which band is used.

[0039] Note that the E-UTRA list of LTE bands is by no means a final list but, rather, it evolves as new spectrum is allocated to mobile operators and as devices are specified to use that spectrum. New bands are specified either in spectrums without any current bands overlapping their frequencies, or in spectra in bands that overlap frequencies from previous band allocations. For example, Band 44, a TDD band spanning 703 to 803 MHz, was added as an E-UTRA band a few years after the specification of older 700 MHz FDD bands such as Bands 12, 13, 14, and 17.

[0040] As can be seen in Figure 6, the largest volume of data on mobile devices used to be voice data (e.g. in the first quarter (Q1) of 2007), which is highly symmetric. However, with the introduction of the iPhone in 2007, the rapid adoption of Android, and then the introduction of the iPad in 2009, non-voice mobile data quickly outpaced the growth of voice data to the point where, in In mid-2013, voice data was a small fraction of data traffic on mobile devices. The forecast is that non-voice data will continue to grow exponentially, increasingly overtaking voice data.

[0041] As can be seen in Figure 7, non-voice mobile data is largely dominated by media such as streaming video, audio, and web browsing (much of which includes streaming video). While some streaming media is UL data (for example, during a video conference), the vast majority is DL data, which causes highly asymmetric use of DL versus UL data. For example, in the Financial Times publication of May 28, 2013, the article "Asymmetry and the impending (US) spectrum crisis", it is stated that "...industry estimates for the ratio of downlink data traffic and uplink data traffic is between a ratio of about eight to one (8:1) and considerably more." The article then points out that mostly FDD installations in the US are very inefficient to deal with such asymmetry, as FDD mode allocates the same amount of spectrum to each of DL and UL. As another example, Qualcomm estimated DL/UL traffic asymmetry to be as high as 9:1 for one of the US carriers, based on 2009 measurements on active networks (cf., Qualcomm, "1000x: more spectrum especially for small cells", November 2013, http://www.qualcomm.com/media/documents/files/1000x-more-spectrum- especially-for-small-cells.pdf). Thus, even when FDD DL spectrum is being heavily used (potentially to the point of being overloaded), UL spectrum may be largely unused.

[0042] The Financial Times article points out that TDD is much better suited to this asymmetry, as it can be configured to allocate many more time slots to DL data than to UL data. For example, in the case where 20 MHz is allocated to FDD (such as 10+10 MHz), the DL data rate is limited to a maximum full-time usage of 10 MHz (even when UL data needs much less than the 10 MHz allocated to them), while with 20 MHz allocated to TDD, the DL data rate can use the full 20 MHz most of the time, allocating 20 MHz to UL data during a small percentage of the time. time, adapting much better to current data usage characteristics. The article acknowledges that, unfortunately, most of the existing mobile spectrum in the US is already committed to FDD mode, but calls on the FCC to encourage the use of TDD as it allocates new spectrum.

[0043] While TDD could certainly enable more efficient use of new spectrum allocations, given the increasingly asymmetric nature of mobile data, unfortunately existing FDD network installations cannot switch their mode of operation to TDD as the vast Most users of these LTE FDD networks have devices that only support FDD mode, and their devices would no longer be able to connect if the network were switched to TDD mode. Consequently, as data usage in LTE becomes increasingly asymmetric, existing LTE FDD networks will see increasing DL congestion, while UL spectrum will become increasingly underutilized (at a DL:UL ratio of 8:1, the lowest estimate from the May 28, 2013 Financial Times article, this would imply that if the DL channel was being fully used, only 1/8, or the equivalent of 1.25 MHz out of 10 MHz, would be being used in the UL channel). This is a huge waste and a huge inefficiency, particularly when considering the limited physical existence of mobile spectrum that is practical to use (e.g., frequencies that can penetrate walls and propagate well without line of sight, such as ~450 to 2,600 MHz) and the exponential growth of (increasingly asymmetric) mobile data (for example, Cisco VNI 2/2013 predicts a compound annual growth rate (CAGR) of 61% in data growth by 2018, the majority of which is streaming video and other highly asymmetric data).

Brief description of the drawings

[0044] A better understanding of the present invention can be obtained from the following detailed description, together with the drawings, in which:

[0045] Figure 1 illustrates the general structure of the DIDO radio access network (DRAN, for "DIDO Radio Access Network").

[0046] Figure 2 illustrates the virtual radio instance (VRI) protocol stack compatible with the OSI model and the LTE standard.

[0047] Figure 3 illustrates adjacent DRANs to extend coverage in DIDO wireless networks.

[0048] Figure 4 illustrates the handoff between a DRAN and adjacent wireless networks.

[0049] Figure 5 illustrates the handoff between a DRAN and LTE cellular networks.

[0050] Figure 6 is prior art showing the use of voice and non-voice data from the mobile spectrum, from 2007 to 2013.

[0051] Figure 7 is prior art showing the share of mobile device data traffic by application type in 2012.

[0052] Figure 8 is a prior art comparison between FDD LTE and TDD LTE modes of operation.

[0053] Figure 9 illustrates a new TDD network simultaneously using UL spectrum with an existing FDD network.

[0054] Figure 10 is a prior art chart of duplex TDD LTE configurations.

[0055] Figure 11 illustrates a new TDD network simultaneously using DL spectrum with an existing FDD network.

[0056] Figure 12 illustrates two new TDD networks simultaneously using UL and DL spectrum with an existing FDD network.

[0057] Figure 13 illustrates a new FDD network simultaneously using UL and DL spectrum with an existing FDD network.

Detailed Description

[0058] One solution to overcome many of the aforementioned limitations of the prior art is to have user devices simultaneously operate in TDD mode in the same spectrum as the currently used UL or DL FDD spectrum, so that the use of the TDD spectrum is coordinated so as not to conflict with the current use of the FDD spectrum. Particularly in the FDD UL channel, there is more and more unused spectrum, and TDD devices could use that spectrum without impacting the speed of the existing FDD network. This also allows the use of TDD in the UHF spectrum, which is highly efficient for propagation and which, in many regions of the world, is almost entirely allocated to FDD, relegating TDD to the much less efficient microwave bands. in terms of propagation.

[0059] In another embodiment, it is to have user devices simultaneously operate in FDD mode in the same spectrum as the currently used UL or DL FDD spectrum, so that the UL and DL channels are reversed and the use of the spectrum of each network is coordinated so as not to conflict with the spectrum use of the other network. As each network's UL channel is increasingly underutilized relative to the DL channel, this makes it possible for each network's DL channel to use spectrum not used in the other network's UL channel.

[0060] Additionally, in each of the modalities, spectral efficiency can be vastly increased by implementing one or both networks using distributed input and distributed output (DIDO) technology. ), as described in the patents, patent applications and provisional applications mentioned below, all of which are granted to the assignee of this patent, and are incorporated by reference. Such patents, patent applications and provisional patent applications are sometimes collectively referred to herein as "patents and related patent applications."

[0061] U.S. Provisional Application Serial No. 61/937,273, entitled "Systems and Methods for Mapping Virtual Radio Instances into Physical Areas to Coherence in Distributed Antenna Wireless Systems";

[0062] US Application Serial No. 14/156,254, entitled "System and Method For Distributed Antenna Wireless Communications";

[0063] US Application Serial No. 14/086,700, entitled "Systems and Methods for Exploiting Inter-cell Multiplexing Gain in Wireless Cellular Systems Via Distributed Input Distributed Output Technology";

[0064] US Application Serial No. 14/023,302, entitled "Systems And Methods To Coordinate Transmissions In Distributed Wireless Systems Via User Clustering";

[0065] US Application Serial No. 13/844,355, entitled "Systems and Methods for Radio Frequency Calibration Exploiting Channel Reciprocity in Distributed Input Distributed Output Wireless Communications";

[0066] US Application Serial No. 13/797,984, entitled "Systems and Methods for Exploiting Inter-cell Multiplexing Gain in Wireless Cellular Systems Via Distributed Input Distributed Output Technology";

[0067] US Application Serial No. 13/797,971, entitled "Systems and Methods for Exploiting Inter-cell Multiplexing Gain in Wireless Cellular Systems Via Distributed Input Distributed Output Technology";

[0068] US Application Serial No. 13/797,950, entitled "Systems and Methods for Exploiting Inter-cell Multiplexing Gain in Wireless Cellular Systems Via Distributed Input Distributed Output Technology";

[0069] US Application Serial No. 3/633,702, entitled "Systems and Methods for Wireless Backhaul in Distributed-Input Distributed-Output Wireless Systems";

[0070] US Application Serial No. 13/475,598, entitled "Systems and Methods to enhance spatial diversity in distributed-input distributed-output wireless systems";

[0071] US Application Serial No. 13/464,648, entitled "System and Methods to Compensate for Doppler Effects in Distributed-Input Distributed Output Systems";

[0072] US Application Serial No. 13/233,006, entitled "System and Methods for planned evolution and obsolescence of multiuser spectrum";

[0073] US Application Serial No. 13/23,996, entitled "Systems and Methods to Exploit Areas of Coherence in Wireless Systems";

[0074] US Application Serial No. 12/802,989, entitled "System And Method For Managing Handoff Of A Client Between Different Distributed-Input-Distributed-Output (DIDO) Networks Based On Detected Velocity Of The Client";

[0075] US Application Serial No. 12/802,988, entitled "Interference Management, Handoff, Power Control And Link Adaptation In Distributed-Input Distributed-Output (DIDO) Communication Systems";

[0076] US Application Serial No. 12/802,975, entitled "System And Method For Link adaptation In DIDO Multicarrier Systems";

[0077] US Application Serial No. 12/802,974, entitled "System And Method For Managing Inter-Cluster Handoff Of Clients Which Traverse Multiple DIDO Clusters";

[0078] US Application Serial No. 12/802,958, entitled "System And Method For Power Control And Antenna Grouping In A Distributed-Input-Distributed-Output (DIDO) Network";

[0079] US Patent No. 8,654,815, granted on Tuesday, February 18, 2014, entitled "System and Method for Distributed Input Distributed Output Wireless Communications";

[0080] US Patent No. 8,571,086, granted on October 29, 2013, entitled "System and Method for DIDO precoding interpolation in multicarrier systems";

[0081] US Patent No. 8,542,763, granted on September 24, 2013, entitled "Systems And Methods to coordinate transmissions in distributed wireless systems via user clustering";

[0082] US Patent No. 8,428,162, granted on April 23, 2013, entitled "System and Method for Distributed Input Distributed Output Wireless Communication";

[0083] US Patent No. 8,170,081 granted on May 1, 2012, entitled "System And Method For Adjusting DIDO Interference Cancellation Based On Signal Strength Measurements";

[0084] US Patent No. 8,160,121, granted on April 17, 2012, entitled "System and Method For Distributed Input-Distributed Output Wireless Communications";

[0085] US Patent No. 7,885,354, granted on February 8, 2011, entitled "System and Method For Enhancing Near Vertical Incidence Skywave ("NVIS") Communication Using Space-Time Coding";

[0086] US Patent No. 7,711,030, granted on May 4, 2010, entitled "System and Method For Spatial-Multiplexed Tropospheric Scatter Communications";

[0087] US Patent No. 7,636,381, granted on December 22, 2009, entitled "System and Method for Distributed Input Distributed Output Wireless Communication";

[0088] US Patent No. 7,633,994, granted on December 15, 2009, entitled "System and Method for Distributed Input Distributed Output Wireless Communication";

[0089] US Patent No. 7,599,420, granted on October 6, 2009, entitled "System and Method for Distributed Input Distributed Output Wireless Communication";

[0090] US Patent No. 7,418,053, granted on August 26, 2008, entitled "System and Method for Distributed Input Distributed Output Wireless Communication";

[0091] The present invention discloses systems and methods for concomitant use of spectrum within the actively used spectrum. Some of the embodiments use the distributed input and distributed output and MU-MAS technology previously disclosed by the assignee of the present patent. The disclosures in Section 1 and Section 2, below, correspond to the disclosures in US Provisional Application Serial No. 61/937,273, filed February 7, 2014, entitled "Systems and Methods for Mapping Virtual Radio Instances into Physical Areas to Coherence in Distributed Antenna Wireless Systems" and related to the present invention.

1. Systems and methods for mapping VRIs in areas of coherence

[0092] An embodiment of the present invention discloses systems and methods for providing multiple, simultaneous, non-interfering data streams within the same frequency band, between a network and a plurality of coherence areas on a wireless link through virtual radio instances (VRIs). In one embodiment, the system is a multiuser multiple antenna system (MUMAS) as depicted in Figure 1. The color-coded units in Figure 1 show the one-to-one mapping. -one between the data sources 101, the VRIs 106 and the coherence areas 103, as described below.

1.1 System architecture overview

[0093] In Figure 1, data sources 101 are files or data streams carrying web content or files on a local or remote server, such as text, images, sounds, videos, or combinations thereof. One or more files or data streams are sent or received between network 102 and each coherence area 103 on wireless link 110. In one embodiment, the network is the Internet or any wired or wireless local area network.

[0094] The coherence area is a volume in space where waveforms coming from different antennas of the MU-MAS sum coherently in such a way that only the data output 112 of a VRI is received within that coherence area, without any interference from other data output from other VRIs sent simultaneously over the same wireless link. In the present patent application, the term "coherence area" is used to describe coherence volumes or private cells (e.g., "pCells™" 103), as described in our previous patent application [US patent application no. series 13/232,996, entitled "Systems and Methods to Exploit Areas of Coherence in Wireless Systems"]. In one embodiment, the coherence areas correspond to the locations of user equipment (UE) 111 or wireless network subscribers, each subscriber being associated with one or multiple data sources 101. The coherence areas may have sizes and shapes varied, depending on propagation conditions, as well as the type of MU-MAS precoding techniques employed to generate them. In one embodiment of the invention, the MU-MAS precoder dynamically adjusts the size and shape of the coherence areas to adapt to changing propagation conditions while providing users with content with good link reliability.

[0095] The data sources 101 are first sent via Network 102 to the DIDO radio access network (DRAN) 104. Then, the DRAN translates the files or data streams into a format that can be received by the UEs 103, and sends the files or data streams simultaneously to the plurality of coherence areas, such that each UE receives its own files or data streams without interference from other files or data streams sent to other UEs. The DRAN 110 consists of a gateway 105 as the interface between the network and the VRIs 106. The VRIs transform packets being routed through the gateway into data streams 112, either as raw data, or as a packet structure that is sent to a baseband unit of a MU-MAS. In one embodiment, the VRI comprises the open systems interconnection (OSI) protocol stack, which consists of seven layers: applications, presentation, session, transport, network, data link, and physical, as per represented in Figure 2a. In another embodiment, the VRI comprises only a subset of the OSI layers.

[0096] In another embodiment, VRIs are defined based on different wireless network standards. By way of example, but not limitation, a first VRI consists of the GSM standard protocol stack, a second VRI, of the 3G standard, a third VRI, of the HSPA+ standard, a fourth VRI, of the LTE standard, a fifth VRI, of the LTE-A standard and a sixth VRI, of the Wi-Fi standard. In an exemplary embodiment, the VRIs comprise the control plane or user plane protocol stack, defined by the LTE standards. The user plane protocol stack is shown in Figure 2b. Every UE 202 communicates with its own VRI 204 through the PHY, MAC, RLC, and PDCP layers, with the gateway 203 through the IP layer, and with the network 205 through the application layer. For the control plane protocol stack, the UE also communicates directly with the mobility management entity (MME) through the NAS layer (as defined in the LTE standard stack).

[0097] The virtual connection manager (VCM) 107 is responsible for assigning the PHY layer identity of the UEs (e.g., radio network temporary identifier (RNTI) ) cell-specific), and VRI and UE authentication and mobility. The data streams 112 at the output of the VRIs are provided to the Virtual Radio Manager (VRM) 108. The VRM comprises a task scheduler unit (which schedules the DL (downlink) and UL (uplink) packets) for different UEs), a baseband unit (e.g. comprising a FEC encoder/decoder, modulator/demodulator, resource grid creator) and a MU-MAS baseband processor (consisting of precoding logic to implement precoding operations). In one embodiment, data streams 112 are I/Q samples at the output of the PHY layer in Figure 2b, which are processed by the MU-MAS baseband processor. In a different embodiment, data streams 112 are MAC, RLC, or PDCP packets sent to a scheduling unit that forwards them to a baseband unit. The baseband unit converts the packets into I/Q supplied to the MU-MAS baseband processor.

[0098] The MU-MAS baseband processor is the core of the VRM that converts M I/Q samples from the M VRIs into N data streams 113 sent to access points (APs) 109. In one embodiment , the data streams 113 are I/Q samples of the N waveforms transmitted over the wireless link 110 of the APs 109. In this embodiment, the APs consist of an ADC/DAC RF chain and antenna. In a different embodiment, the data streams 113 are bits of information and MU-MAS precoding information that are combined at the APs to generate the N waveforms sent over the wireless link 110. In this embodiment, each AP is equipped with CPU, DSP or SoC to perform additional baseband processing, before ADC/DAC units.

1.2 Mobility and handoff support

[0099] The systems and methods described up to this point work as long as the UEs are within range of the APs. When the UEs leave the PA's coverage area, the link may be lost and the DRAN 301 cannot create areas of coherence. To extend the coverage area, systems can gradually expand by adding new APs. However, there may not be enough processing power in the VRM to support new APs, or there may be practical installation issues in connecting the new APs to the same VRM. In these scenarios, it is necessary to add adjacent DRANs 302 and 303 to support the new APs, as shown in Figure 3.

[0100] In one embodiment, a given UE is located within the coverage area served by both the first DRAN 301 and the adjacent DRAN 302. In this embodiment, the adjacent DRAN 302 only performs MU-MAS baseband processing for that UE, along with the MU-MAS processing of the first DRAN 301. No VRIs are handled by the adjacent DRAN 302 for the given UE, since the VRI for that UE is already running within the first DRAN 301. To enable joint precoding between the first DRAN and the adjacent DRAN, baseband information is exchanged between the VRM of the first DRAN 301 and the VRM of the adjacent DRAN 302 through cloud VRM 304 and links 305. Links 305 are any type of wired (e.g., fiber, DSL, cable) or wireless (e.g., line-of-sight links) connection that can support adequate quality (e.g., sufficiently low latency and adequate transmission rate) to avoid performance degradation of the MUMAS precoder.

[0101] In a different embodiment, a given UE leaves the coverage area of the first DRAN 301 and enters the coverage area of the adjacent DRAN 303. In this embodiment, the VRI associated with that UE is "teleported" from the first DRAN 301 to the adjacent DRAN 303. By "VRI being teleported" or "VRI teleportation" we mean that the state information of the VRI is transferred from the DAN 301 to the DRAN 303, and the VRI stops working on the DRAN 301 and starts working on the DRAN 303. Ideally , the VRI teleportation occurs quickly enough, from the point of view of the UE being served by the teleported VRI, that no discontinuity in the VRI data flow is noticed. In one embodiment, if there is a delay for the VRI to become fully functional after it has been teleported, then, before VRI teleportation begins, the UE served by that VRI is placed in a state in which it does not lose connection or enter an undesirable state until the VRI begins functioning in the adjacent DRAN 303, and the UE is again served by a functioning VRI. "VRI teleportation" is enabled by the cloud VCM 306 that connects the VCM of the first DRAN 301 with the VCM of the adjacent DRAN 303. Wired or wireless links 307 between VCMs do not have the same restrictive limitations as links 305 between VRMs, as they only carry data and do not affect the precoding performance of the MU-MAS. In the same embodiment of the invention, additional links 305 are used between the first DRAN 301 and the adjacent DRAN 303 to connect their VRMs that can support adequate connection quality (e.g., sufficiently low latency and adequate transmission rate) to avoid degradation performance of MU-MAS precoding. In one embodiment of the invention, the gateways of the first DRAN and the adjacent DRAN are connected to the cloud gateway 308 that manages all translation of network addresses (or IP addresses) across the DRANs.

[0102] In one embodiment of the invention, VRI teleportation occurs between the DRAN network 401 disclosed in the present application and any adjacent wireless network 401, as shown in Figure 4. By way of example, but not limitation, the wireless network wire 401 is any conventional cellular network (e.g., GSM, 3G, HSPA+, LTE, LTE-A) or wireless local area network (WLAN, e.g., Wi-Fi). As the VRI is teleported from the DRAN to the adjacent wireless network 401, the UE is passed from one network to the other and its wireless connection can continue.

[0103] In one embodiment, the adjacent wireless network 401 is the LTE network shown in Figure 5. In this embodiment, the cloud VCM 502 is connected to the LTE mobility management entity (MME) 501 All identity, authentication and mobility information for each UE being passed between the LTE and DRAN networks is exchanged between the MME 501 and the cloud VCM 502. In the same embodiment, the MME is connected to one or multiple eNodeBs 503 that connect to the UE 504 via the wireless cellular network. The eNodeB nodes are connected to the network 507 through the service gateway (S-GW) 505 and the packet data network gateway (P-GW) 506.

2. Systems and methods for DL and UL processing of MU-MAS

[0104] Typical wireless downlinks (DL) are physical channels carrying information for the entire cell, and dedicated physical channels carrying information and data for a given UE. For example, the LTE standard defines broadcast channels such as P-SS and S-SS (used for synchronization in the UE), MIB and PDCCH (Physical Downlink Control Channel), as well as channels for carrying data to a given UE as the PDSCH (Physical Downlink Shared Channel). In one embodiment of the present invention, all LTE broadcast channels (e.g., P-SS, S-SS, MIC, PDCCH) are pre-coded such that each UE receives its own dedicated information. In a different embodiment, part of the broadcast channel is pre-coded, part is not. By way of example, but not limitation, the PDCCH contains broadcast information and also information dedicated to a single UE, such as DCI 1A and DCI 0 used to point the UE to the RBs (resource blocks). to be used on downlink (DL) and uplink (UL) channels. In one embodiment, the broadcast portion of the PDCCH is not precoded, but the portion containing DCI 1A and 0 is precoded such that each UE obtains its own dedicated information about the data-carrying RBs.

[0105] In another embodiment of the invention, precoding is applied to all or only part of the data channels, such as PDSCH in LTE systems. By applying precoding to the entire data channel, an embodiment of the MU-MAS disclosed in the present application allocates the entire bandwidth to each UE, and the plurality of data streams and the plurality of UEs are separated by means of spatial processing. In typical scenarios, however, most, if not all, UEs do not need the full bandwidth (e.g. ~70 Mbps per UE, peak data rate for TDD configuration #2 on 20 MHz of spectrum). Then, an embodiment of the MU-MAS in the present application subdivides the RBs of DL RBs into multiple blocks, as in OFDMA systems, and assigns each block to a subset of UEs. UEs within the same block are separated using MU-MAS precoding. In another embodiment, the MU-MAS allocates different DL subframes to different subsets of UEs, thereby dividing the DL as in TDMA systems. In yet another embodiment, the MU-MAS at the same time subdivides the DL RBs into multiple blocks as in OFDMA systems between subsets of UEs and also allocates different subframes to different subsets of UEs as in TDMA systems, thus using both OFDMA and TDMA to divide processing capacity. For example, if there are 10 APs in a TDD #2 configuration at 20 MHz, then there is an aggregate DL capacity of 70 Mbps * 10 = 700 Mbps. If there are 10 UEs, then each UE can receive 70 Mbps at the same time. If there are 200 UEs, and the aggregate processing capacity is divided equally, then using OFDMA, TDMA, or a combination thereof, the 200 UEs would be divided into 20 groups of 10 UEs, so that each UE would receive 700 Mbps /200 = 3.5 Mbps. In another example, if 10 UEs needed 20 Mbps, and the other UEs were to equally share the remaining processing capacity, then 20 Mbps*10 = 200 Mbps of the 700 Mbps would be used for 10 UEs, leaving 700 Mbps-200 Mbps = 500 Mbps to be divided among the remaining 200-10 = 190 UEs. This way, each of the remaining 90 UEs would receive 500 Mbps/190 = 2.63 Mbps. Thus, many more UEs than APs can be supported in the MU-MAS system of the present invention, and the aggregate processing capacity of all APs can be divided among many UEs.

[0106] In the UL channel, the LTE standard defines conventional multiple access techniques, such as TDMA or SC-FDMA. In one embodiment of the present invention, MU-MAS precoding is enabled through the DL in order to assign UL grants to different UEs to enable TDMA and SC-FDMA multiple access techniques. As such, the aggregate UL speed can be divided among many more UEs than there are APs.

[0107] Where there are more UEs than APs and the aggregate processing capacity is divided among the UEs, as described above, the MU-MAS system supports one VRI for each UE, and the VRM controls the VRIs so that these VRIs use RBs and resource grants to work with the chosen OFDMA, TDMA, or SC-FDMA systems used to subdivide aggregate processing capacity. In another embodiment, one or more individual VRIs can support multiple UEs and manage the distribution of processing capacity among these UEs using OFDMA, TDMA or SC-FDMA techniques.

[0108] In another embodiment, the distribution of processing capacity is based on load balancing user demand, using any of the many prior art techniques, depending on the policies and performance objectives of the system. In another embodiment, distribution is based on QoS (Quality of Service) requirements for specific UEs (e.g., paying for a specific level of service, guaranteeing specific levels of processing capacity) or for specific data types (e.g. example, video for a television service).

[0109] In a different embodiment, a UL receiving antenna selection is applied to improve quality. In this method, the channel quality of UL is estimated in the VRM based on signaling information sent by the UEs (e.g., SRS, DMRS) and the VRM chooses the best receiving antennas for different UEs in the UL. Then, the VRM assigns a receiving antenna to each UE to improve its link quality. In a different embodiment, the selection of the receiving antenna is employed to reduce cross-interference between frequency bands due to the SC-FDMA scheme. A significant advantage of this method is that the UE transmits over the UL only to the AP closest to its location. In this scenario, the UE can significantly reduce its transmission power to reach the nearest AP, thereby improving battery life. In the same embodiment, different power scaling factors are used for the UL data channel and the UL signaling channel. In an exemplary embodiment, the power of the UL signaling channel (e.g., SRS) is increased compared to the data channel to allow UL CSI estimation and MU-MAS precoding (taking advantage of reciprocity). of UL/DL channels in TDD systems) from many APs, but still limiting the power required for UL data transmission. In the same embodiment, the power levels of the UL signaling and UL data channels are adjusted by the VRM through DL signaling based on transmission power control methods that equalize the relative power sent to and received from different UEs. .

[0110] In a different embodiment, a maximum ratio combining (MRC) is applied to the UL receiver to improve the quality of the signal coming from all UEs to the plurality of APs. In a different embodiment, a zero-force (ZF), minimum mean squared error (MMSE), successive interference cancellation (SIC) or other non-linear technique or the same precoding technique used for DL precoding is applied to the UL to differentiate data streams being received from different coherence areas of UEs. In the same embodiment, receive spatial processing is applied to the UL data channel (e.g., PUSCH) or the UL control channel (e.g., PUCCH) or both.

3. Systems and methods for concomitant use of spectrum within the actively used spectrum

[0111] As detailed in the Background section above and shown in Figures 6 and 7, the use of mobile data has changed dramatically from the predominance of largely symmetric voice data to that of highly asymmetric non-voice data, particularly media such as streaming video. The majority of LTE installations worldwide are FDD LTE, whose physical layer structure is illustrated in the top half of Figure 8, which has fixed, symmetric uplink ("UL") and downlink ("DL") channels. and as a result, as DL channels have become increasingly congested with the exponential growth of DL data compared to UL data, UL data channels have become increasingly underutilized.

[0112] The LTE standard also supports TDD LTE (also called "TD-LTE"), whose physical layer structure is illustrated in the lower half of Figure 8, and the mobile operator can choose whether the UL and DL channels are symmetric ( as shown in this illustration) or asymmetric (for example, with more subframes allocated to either the DL channel or the UL channel), and as a result, as the DL channels become increasingly congested with the exponential growth of DL data relative to to UL data, the mobile operator can choose to allocate more subframes to DL than to UL. In one configuration, for example, TD-LTE supports a DL:UL ratio of 8:1, allocating 8 times more subframes to DL than to UL.

[0113] Other than the fact that TD-LTE is bidirectional on one channel, the structure and details of TD-LTE and FDD LTE are almost identical. In both modes, each frame lasts 10 ms and consists of ten subframes of 1 ms each. The modulation and coding schemes are almost identical, and the upper layers of the protocol stack are effectively the same. In both cases, the time and frequency reference for the user equipment ("UE") devices (e.g. mobile phones, tablets) is provided by the eNodeB (the LTE base station protocol stack) for all devices (through the DL channel with FDD LTE and during DL subframes with TD-LTE).

[0114] Notably, in the case of both FDD and TDD LTE, the network can be configured so that a UE can only transmit UL data when it is given by the eNodeB a concession to do so, received through a transmission of DL. In this way, the eNodeB not only controls when it transmits DL data, but also controls when UEs can transmit UL data.

[0115] Furthermore, notably, in the case of an LTE FDD UE, its receiver is only tuned to its DL channel, and does not have any receiver tuned to its UL channel. In this way, a UE FDD is "deaf" to anything that is transmitted on its UL channel by another device.

[0116] And, in the case of all LTE UEs, whether FDD or TDD, even to the extent that their receivers are tuned to a specific channel, except for certain control signals intended for all UEs (or a given UE ) that maintain their time reference and network connection, or that give them instructions on what time and frequency to receive data, ignore DL data not intended for them. Or, to put it another way, the only DL data relevant to an LTE UE is data that is either control information, or is UE-directed data. During other times, whether the channel is being used with a DL for another UE, not used for anything, or used for a purpose that is outside the LTE standard, the UE is "deaf" to any DL transmissions other than control information or DL data addressed to that UE. Thus, LTE receivers, whether FDD or TDD, only receive control data intended for all UEs or a given UE, or receive data for a given UE. Other transmissions on the DL channel are ignored.

[0117] Figure 9 illustrates how an FDD and TDD network can simultaneously use actively used FDD spectrum. The top two rows of boxes, labeled "FDD LTE 910", illustrate an LTE frame interval (10 ms) made up of ten 1 ms subframe intervals on both the uplink ("UL") and downlink channels. descendant ("DL"). This illustration shows the type of asymmetric data transmission that is increasingly typical (for example, downlink video streaming), where there is much more DL data than UL data. Boxes with solid outlines filled with slanted lines (e.g., box 912 and boxes 911) indicate subframes where data is being transmitted, boxes with dotted outlines that are empty (e.g., boxes 914) show "idle" subframes where no data is present. is being transmitted (that is, there is no transmission on the channel during that subframe interval). The 911 boxes are 2 of 10 DL subframes, all of which are full of data. Box 912 shows 1 UL subframe, which has data. And the 914 boxes are 3 of 9 idle UL subframes, which have no data transmissions.

[0118] The two central rows of boxes in Figure 9, labeled "TDD LTE 920", illustrate an LTE frame interval (10 ms) formed by 10 1 ms subframe intervals, including 2 "Special" subframe intervals but , unlike the FDD LTE 910 rows, both rows of boxes in the TDD LTE 920 row not only share the same spectrum with each other, they share the same spectrum as the FDD uplink. This illustration shows asymmetric data transmission where there are 4 DL subframes and 3 UL subframes transmitting data. The solid-outlined boxes filled with dashed lines (e.g., box 921, box 922, and box 923) indicate subframes where data is being transmitted; the dotted-outlined box that is empty (e.g., box 924) shows a "subframe" idle" where no data is being transmitted (i.e., there is no transmission on the channel during the interval of that subframe). Box 921 is 1 of 4 DL subframes, all of which are full of data. Box 922 shows 1 of 3 UL subframes, all of which have data. Box 924 is the 1 idle UL subframe, which is empty.

[0119] The third two rows of boxes in Figure 9, labeled "FDD+TDD LTE 930", illustrate an LTE frame interval (10 ms) formed by 10 1 ms subframe intervals, including 2 "Special" subframe intervals. ", and show the simultaneous operation of the FDD LTE 910 system and the TDD LTE 920 system, with the TDD LTE 920 system sharing the same spectrum as the FDD LTE 910 uplink. The two systems do not interfere with each other because, (the ) during the subframe interval 912, where the FDD LTE system 910 has UL data transmission, the TDD LTE system 920 has an idle interval 924 when it is neither UL nor DL, and (b) during the subframe intervals, where the TDD LTE 920 system has transmissions in the UL or DL direction (e.g. 921, 923 and 922), the FDD LTE 910 system has UL idle slots (e.g. UL 914 idle subframes) without any UL data transmissions. This way, the two systems coexist using the same spectrum, without any interference between them.

[0120] For the FDD LTE 910 and TDD LTE 920 networks to simultaneously use the same spectrum, their operation needs to be coordinated by one of the eNodeB that is configured to simultaneously operate two networks sharing spectrum, or by the coordination of an eNodeB operating the TDD network existing LTE 920 and a second network controller that could be a second eNodeB or another system compatible with LTE frame timing, such as the DIDO MU-MAS C-RAN antenna system, disclosed in Sections 1 and 2 above and in Patents and Related Applications section. In any of these cases, both frames of the FDD LTE 910 and TDD LTE 920 systems need to be synchronized, not only in terms of timing, but also in terms of subframe resource allocations. For example, in the case of Figure 9, the system controlling the FDD LTE 910 system will need to be aware of which subframes are TDD UL subframes that are available to be used for UL (e.g., will not conflict with TDD DL control signals sent through subframes #0 and #5 for time and frequency synchronization in the UE), and use one of those subframes for your UL 912 FDD subframe. If the same system is also controlling the TDD LTE 920 system, you will also need to make sure not schedule a UL from a TDD device during that 912 subframe, and if you are not controlling the TDD LTE 920 system, you will need to notify any system that is controlling the TDD LTE 920 system so that it does not schedule a UL from a TDD device TDD during that subframe 912. Of course, it may occur that the FDD LTE 910 system requires more than one UL subframe during a frame time, and if so, its controller would use any, or all, of the 3 subframes 922 of TDD LTE 920 to its UL subframes, appropriately controlling or notifying as described above. Note that it may be the case that, in some of the 10 ms frames, all UL subframes are allocated to one of the networks, and the other network does not get any UL subframes. LTE devices do not expect to be able to transmit UL data every frame time (for example, when an LTE network is congested, an LTE device may wait many frame times before it is granted at least a portion of a subframe of UL), such that an embodiment of the present invention will operate when all TDD LTE 920 UL subframes available in a given frame are used by one network (i.e., leaving the other network "devoid" of UL subframes). However, starving a network for too many successive frames, or allowing too few UL frames in aggregate, will result in poor network performance (e.g., low UL speed, or high round-trip latency) and, at some point, if LTE devices connected to the network seeking to transmit UL data may determine that the network is unusable and disconnect. Therefore, establishing appropriate priorities and scheduling paradigms to balance UL subframe resources between the FDD LTE 910 and TDD LTE 920 networks can result in the best overall network performance and the best user (and/or UE) experience.

[0121] A tool that is available to balance UL subframe resources (and to meet network operator priorities) that is not available in a standalone FDD LTE system is the TDD LTE Duplex Settings, shown in Figure 10. Figure 9 illustrates TDD LTE Duplex Configuration 1 of the TDD LTE 920 system where, during the 10 subframes in the 10 ms frame, there are 4 UL subframes, 4 DL subframes, and 2 Special subframes. As can be seen in Figure 10, there are several TDD LTE Duplex Configurations that can be used, depending on mobile operator needs and data traffic patterns, and to balance UL subframe resources with FDD LTE network needs. 910. The LTE Duplex TDD Configuration can also be changed over time as data traffic patterns change. Any of the TDD LTE Duplex Configurations can be used with the present invention. For example, in Configuration 1, as shown in Figure 9, 1 UL subframe was allocated to the FDD network and 3 UL subframes were assigned to the TDD network. If the FDD network had a sudden need for more UL speed, then 2 UL subframes could be allocated to FDD, leaving 2 for TDD, already at the next frame time. Therefore, switching UL subframe allocation between FDD and TDD networks can be extremely dynamic.

[0122] Note that, if desired, the allocation of UL resources between the FDD LTE 910 and TDD LTE 920 networks can be even finer grained than a subframe basis. It is possible to allocate some resource blocks within a single subframe to FDD devices, and others to TDD devices. For example, the LTE standard uses the SC-FDMA multiple access technique for the UL channel. In this way, the UL channels of FDD and TDD devices can be assigned to different resource blocks within the same subframe through the SC-FDMA scheme.

[0123] Finally, it is possible to schedule an FDD LTE 910 UL during what would otherwise be a DL or Special TDD LTE 920 subframe. One consideration is that the DL TDD control signals used by the TDD LTE UEs to maintain their connections and maintain timing (e.g., P-SS and S-SS broadcast signals sent through subframes #0 and #5) need to be received by the TDD LTE UEs with sufficient regularity, otherwise the UEs may disconnect.

[0124] Figure 11 shows the same concept as Figure 9 and described above, except that the shared channel is the DL FDD channel, not the UL FDD channel. The same fill and outline designations of the subframes of Figure 9 are used in Figure 11 and, as can be seen, the traffic situation in FDD is reversed with all UL channel subframes of the FDD LTE 1110 being used for data, while only 1 of the FDD LTE 1110's DL subframes is used for data, and while all other DL subframes are "idle" and not transmitting data. Similarly, all TDD LTE 1120 UL subframes are used for data, while all but one of the TDD LTE 1120 DL subframes are used for data, in which case the TDD LTE 1120 LTE channel has the same frequency as the FDD LTE channel 1110 DL. The result of the combined FDD LTE 1110 and TDD LTE 1120 networks is shown in the FDD+TDD LTE 1120 channels. As with the example in Figure 9, the two networks can be controlled by a single controller, or by coordinating multiple controllers, with scheduling between them to ensure that both networks operate as desired by the network operator, with adequate performance for users and user devices.

[0125] Note that FDD devices connected to the FDD LTE 1110 network are relying on DL transmissions for control and timing information as well as data, and need to receive appropriate control signals on a sufficiently regular basis so that stay connected. In one embodiment of the invention, the FDD devices use the broadcast signal sent by the TDD LTE network 1120 through the DL subframes (e.g., subframes #0 and #5) to achieve time and frequency synchronization. In a different embodiment, subframes #0 and #5 carrying broadcast signals are assigned to the FDD LTE network 1110 and used for time and frequency synchronization derivation on each FDD device.

[0126] Although, as described above, typically the DL FDD channel is much more congested than the UL FDD channel, there may be reasons why a mobile operator would wish to share the DL channel. For example, some UL channels are limited to UL use only by the spectrum regulatory authority (for example there may be concerns about output power interfering with adjacent bands). Additionally, once a mobile operator begins offering TDD devices compatible with its FDD spectrum, the mobile operator will likely discover that these devices are using the spectrum more efficiently than FDD devices and thus may discontinue device sales. FDD. As older FDD devices are gradually replaced and an increasing percentage of devices are TDD, the operator may want to allocate more and more of its spectrum to TDD devices but still maintain compatibility with the remaining FDD devices on the market.

[0127] To this end, as fewer and fewer FDD devices remain in operation, the operator may decide to use both the UL and DL bands for TDD operation. This is illustrated in Figure 12, where FDD LTE 1210 has only one subframe in use for UL and one for DL, with the rest being idle. There are two TDD LTE networks, 1220 and 1230, each respectively using the UL and DL channels of FDD LTE 1210, resulting in the two channels being shared by the three networks, as shown in FDD+TDD LTE 1240. The same flexibilities and restrictions apply apply, as previously described, and there can be a single controller for all 3 networks, or multiple controllers. The two TDD networks can be operated independently, or using carrier aggregation techniques.

[0128] An operator may also choose to abandon TDD altogether but instead add a second FDD network in the same spectrum as an existing FDD network, but with the uplink and downlink channels swapped. This is illustrated in Figure 13, where the FDD LTE 1310 network is used very asymmetrically in favor of the DL channel, so only one subframe is used for UL, and a second FDD LTE 1320 network is also very asymmetrically used in favor of the DL channel. DL, but note that in Figure 13 the channel allocation for FDD LTE 1320 is swapped, with the FDD downlink channel shown above the FDD uplink channel, as opposed to the channel order for FDD LTE 1310, or as per shown in previous figures. In the case of both FDD LTE 1310 and 1320, the DL channel leaves an idle DL subframe, which corresponds to a UL frame that is used by the other network. When networks are combined as shown in FDD+TDD LTE 1230, all subframes on both channels are DL, except for subframes 1231 and 1232. This way, 90% of the subframes are dedicated to DL, which better meets network standards. traffic from mobile devices as they have evolved than symmetric spectrum allocation for UL and DL.

[0129] Additionally, this structure allows the controller (or controllers) managing the network to dynamically change the number of UL and DL subframes allocated to each network on a subframe-by-subframe basis, enabling UL traffic adaptation /DL extremely dynamic, despite FDD devices using both networks.

[0130] As with the previously described combined FDD/TDD networks, the same restrictions apply to FDD mode in that LTE devices need to receive sufficient control and timing information to remain connected and function well, and they need to of a sufficiently regular and adequate number of UL tables.

[0131] The two FDD networks can be operated independently, or through carrier aggregation.

[0132] In another embodiment, control information transmitted over the DL channel of an existing active network (for example in Figures 9, 11, 12 and 13, FDD LTE 910, FDD LTE 1110, FDD LTE 1210 or FDD LTE 1310 ) are used by a new network (or networks) using the same channel (for example in Figures 9, 11, 12 and 13, TDD LTE 920, TDD LTE 1120, TDD LTE 1220 and TDD LTE 1230, or FDD LTE 1320) to determine which subframes and/or resource blocks and/or other buckets will be idle. In this way, the one or more new networks can determine when they are able to transmit (either in DL or UL) without interfering with the existing active network. This embodiment may make it possible to simultaneously use the spectrum of the existing active network without any modification of the existing active network, or depend on any special connection with the controller of the existing active network, as it is only a matter of the controller of the one or more new networks receiving which is already in the DL transmission coming from the existing active network. In another embodiment, the only modification to the existing active network is to ensure that it enables the one or more new networks to transmit essential control and timing information to maintain connections with the UEs. For example, the existing active network could be configured to not transmit during times when essential timing and synchronization information is being transmitted but otherwise operate without modification.

[0133] Although the aforementioned modalities of simultaneous support for networks in the same spectrum have used the LTE standard for the examples, similar techniques can also be used with other wireless communication protocols.

4. Using DIDO MU-MAS simultaneously with actively used spectrum

[0134] As disclosed in Sections 1 and 2 and the Patents and Related Applications section, DIDO MU-MAS techniques dramatically increase the capacity of wireless networks, increase reliability and speed per device, and make it possible to also reduce the cost of devices.

[0135] In general, DIDO technology operates more efficiently in TDD networks than in FDD networks, because UL and DL are on the same channel and, as a result, the conductive transmission received on the UL channel can be used to derive information about the channel state to the DL channel by exploiting channel reciprocity. Furthermore, as described, TDD mode is inherently better suited to the asymmetry of mobile data, allowing for more efficient use of spectrum.

[0136] Since the majority of current LTE installations in the world are FDD, using the techniques disclosed in Section 3, it is possible to install a TDD network on spectrum actively used for FDD, and one can use DIDO with this new TDD network , thus dramatically increasing spectrum capacity. This is particularly significant because UHF frequencies propagate much better than microwave frequencies, but most UHF frequencies for mobile devices are already in use by FDD networks. By combining DIDO-based TDD networks with existing FDD networks in the UHF spectrum, an exceptionally efficient TDD network can be deployed. For example, Band 44 is a 703 to 803 MHz TDD band, overlying a large number of 700 MHz FDD bands in the US. Band 44 devices could be used simultaneously in the same spectrum as 700 MHz FDD devices, enabling DIDO FDD in the main spectrum.

[0137] DIDO does not add significant new restrictions to the spectrum matching techniques described above. The DRAN 104, shown in Figure 1, would replace existing eNodeBs in the coverage area or coordinate with existing eNodeBs 401, as shown in Figure 4 by the subframe (or resource block) sharing techniques described above.

[0138] Notably, if the DIDO system is controlling the entire system and providing the eNodeB to the FDD network, then the DIDO may use a driving signal, such as the SRS UL coming from the FDD devices, in order to decode, via spatial processing, the UL of multiple FDD devices existing at the same time and within the same frequency band, thus dramatically increasing the spectral efficiency of the existing FDD UL channel, and also reducing the UL power required (and/or receiving better quality of signal) as distributed DIDO APs are likely closer to the UEs than a single cellular base station, and may also use signal combining techniques such as maximum ratio combining (MRC). ") or other techniques, as previously described for DIDO.

[0139] In this way, DIDO can replace existing eNodeBs and simultaneously use existing spectrum with DIDO TDD devices, while also applying the benefits of DIDO to the UL of existing FDD devices that are already installed.

Claims (5)

1. “SYSTEM” comprising a first wireless network operating in FDD mode, and a second wireless network operating in FDD mode, the second wireless network operating in TDD mode characterized in that the second wireless network comprises a plurality of base stations adjacent networks that share the same cellular ID and simultaneously operate on the same spectrum and in the same geographic area as the first wireless network. 2. “SYSTEM” according to claim 1, characterized by the fact that it comprises a second wireless network operating in TDD mode, which operates in the same spectrum as the uplink in FDD of the first wireless network. 3. “SYSTEM” according to claim 1, characterized by the fact that it comprises the second wireless network operating in TDD mode, which operates in the same spectrum as the downlink in FDD of the first wireless network. 4. “SYSTEM” comprising a first wireless network operates in FDD mode, and a second wireless network operates in FDD mode, characterized by both wireless networks operating simultaneously in the same spectrum and in the same geographic area. 5. “SYSTEM” according to claim 4, characterized by the fact that it additionally comprises the uplink of the first wireless network that operates simultaneously in the same spectrum as the downlink of the second wireless network.