TW201427318A - Systems and methods for wireless backhaul in distributed-input distributed-output wireless systems - Google Patents

Abstract

Systems and methods are described for wireless backhaul in a multiple antenna system (MAS) with multi-user (MU) transmissions (''MU-MAS''). For example, a multiuser (MU) multiple antenna system (MAS) of one embodiment comprises: one or more centralized units communicatively coupled to multiple distributed transceiver stations via a network; the network consisting of wireline or wireless links or a combination of both, employed as a backhaul communication channel; the centralized unit transforming the N streams of information into M streams of bits, each stream of bits being a combination of some or all N streams of information; the M streams of bits being sent over the network to the distributed transceiver stations; the distributed transceiver stations simultaneously sending the streams of bits over wireless links to at least one client device such that at least one client device receives at least one of the original N streams of information.

Description

System and method for wireless backhaul in a wireless system with decentralized input distributed output Related application

This application is a continuation of the following U.S. patent application filed in the same application:

U.S. Application Serial No. 13/475,598, entitled "System and Methods To Enhance Spatial Diversity In Distributed-Input Distributed-Output Wireless Systems."

U.S. Application Serial No. 13/464,648, entitled "System and Methods to Compensate for Doppler Effects in Distributed-Input Distributed Output Systems."

US Application No. 12/917,257 entitled "Systems And Methods To Coordinate Transmissions In Distributed Wireless Systems Via User Clustering"

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

U.S. Patent No. 8,170,081, entitled "System And Method For Adjusting DIDO Interference Cancellation Based On Signal Strength Measurements", issued May 1, 2010.

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

US Application 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"

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

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

US Application No. 12/802,938 entitled "System And Method For DIDO Precoding Interpolation In Multicarrier Systems"

U.S. Application No. 12/630,627 entitled "System and Method For Distributed Antenna Wireless Communications"

US Patent No. 7,599,420, entitled "System and Method for Distributed Input Distributed Output Wireless Communication", dated October 6, 2009; "System and Method for Distributed Input Distributed Output", December 15, 2009 US Patent No. 7,633,994 to Wireless Communication; US Patent No. 7,636,381 entitled "System and Method for Distributed Input Distributed Output Wireless Communication", dated December 22, 2009; For System and Method For Distributed U.S. Patent No. 8,160,121 to Input-Distributed Output Wireless Communications; U.S. Patent No. 7,711,030 entitled "System and Method For Spatial-Multiplexed Tropospheric Scatter Communications", May 4, 2010; August 26, 2008 U.S. Patent No. 7,418,053, entitled "System and Method for Distributed Input Distributed Output Wireless Communication"; "System and Method For Enhancing Near Vertical Incidence Skywave ("NVIS"), awarded on August 2, 2011. U.S. Patent No. 7,885,354 to Communication Using Space-Time Coding.

Prior art multi-user wireless systems increase the complexity of wireless networks and introduce limitations to wireless networks that result in a given user experience (eg, available bandwidth, latency, predictability, reliability) by region The situation in which other users in the spectrum affect the utilization of the spectrum. Considering the increasing demand for aggregated bandwidth in the wireless spectrum shared by multiple users, and for a given user, relying on multi-user wireless network reliability, predictability, and low latency The application continues to grow, and it is clear that prior art multi-user wireless technologies suffer from many limitations. In fact, prior art wireless technologies will not be sufficient for reliable, predictable, and low latency due to the limited availability of spectrum suitable for a particular type of wireless communication (eg, at wavelengths that can effectively penetrate building walls) The increasing demand for bandwidth.

101‧‧‧Centralized processor

102‧‧‧Network

103‧‧‧ transceiver station

104‧‧‧User Equipment (UE)

201‧‧‧Centralized processor

202‧‧‧Router/gateway

203‧‧‧Switch/Hub

204‧‧‧BTS

205‧‧‧High speed wired link

206‧‧‧Wired links

301‧‧‧Centralized processor

302‧‧‧Router/gateway

303‧‧‧Switch/Hub

304‧‧‧BTS

305‧‧‧High speed wired link

306‧‧‧Wired links

307‧‧‧Antenna

308‧‧‧ Access Point (BTS-AP)

309‧‧‧ Repeater (BTS-RP)

401‧‧‧Centralized processor

402‧‧‧Router/gateway

403‧‧‧Switch/Hub

404‧‧‧BTS

405‧‧‧High speed wired link

406‧‧‧Wired links

407‧‧‧Antenna

408‧‧ Access Point (BTS-AP)

409‧‧‧ Repeater (BTS-RP)

410‧‧‧ Repeater (BTS-RP)

501‧‧‧Centralized processor

502‧‧‧Router/gateway

503‧‧‧Switch/Hub

504‧‧‧BTS

505‧‧‧High speed wired link

506‧‧‧Wired links

507‧‧‧Antenna

508‧‧ Access Point (BTS-AP)

509‧‧‧ Repeater (BTS-RP)

510‧‧‧ Repeater (BTS-RP)

901‧‧‧Solar panels

902‧‧‧Charging controller

903‧‧‧Battery

904‧‧‧Inverter

905‧‧‧BTS

906‧‧‧Antenna

907‧‧‧Antenna

1001‧‧‧矽Rected Diode Antenna

1002‧‧‧Charging controller

1003‧‧‧Battery

1004‧‧‧Inverter

1005‧‧‧BTS

1006‧‧‧Antenna

1007‧‧‧Antenna

1102‧‧‧Charging controller

1103‧‧‧Battery

1104‧‧‧Inverter

1105‧‧‧BTS

1106‧‧‧Antenna

1107‧‧‧Antenna/receiver

1201‧‧‧BTS in action

1202‧‧‧Inactive BTS

1203‧‧‧UE

1301‧‧‧BTS

1302‧‧‧BTS

1303‧‧‧UE

1401‧‧‧BTS

1402‧‧‧BTS

1403‧‧‧UE

The patent or application file contains at least one drawing drawn in color. Upon request and payment of the necessary fee, the U.S. Patent and Trademark Office will provide a copy of the color scheme of this patent or patent publication.

A better understanding of the present invention can be obtained from the following detailed description, in which: FIG. 1 illustrates a central transceiver 101, a network 102, and M transceiver stations 103 that wirelessly communicate with N client devices UE1-UE4 One embodiment of a composed MU-MAS; FIG. 2 illustrates a high speed wired link 205 that is interconnected by a plurality of routers or gateways 202 and interconnects the centralized processor 201 to 202 and interconnects the routers or gateways 202 to each other. One embodiment of the composition; FIG. 3 illustrates one embodiment of a BTS-AP 408 that retransmits bitstreams to a plurality of BTS-RPs 409 and 410 via a point-to-multipoint wireless link; FIG. 4 illustrates via point-to-multipoint One embodiment of a BTS-AP 408 that retransmits a bitstream to a plurality of BTS-RPs 409 and 410 by a wireless link; Figure 5 illustrates an embodiment of a DIDO system utilizing a mesh network [5, 7-8] Figure 6 illustrates an example of BSN deployment in the San Francisco (CA) business district; Figure 7 illustrates one embodiment showing two stations in a San Francisco business district with point-to-multipoint links. Note that any BTS-RP may also relay signals to other BTS-NPs as shown on the left side of the figure; Figure 8 illustrates an exemplary mesh network deployment with nodes dispersed around the San Francisco business district; An embodiment of a solar panel 901 connected to a charge controller 902 that charges a battery (the image of the meter is for illustrative purposes only and is not a requirement for a charge controller); FIG. 10 illustrates the use of a 矽 rectifying diode One embodiment of the present invention of the antenna; Figure 11 illustrates one embodiment of a 矽-rectifier diode antenna 1001 combined with an antenna 1007 for a point-to-point/multipoint wireless link to form a receiver; Figure 12 illustrates the transmission bit One embodiment of a typical DIDO network consisting of BTS 1201 and inactive BTS in the role of UE 1203; Figure 13 illustrates one embodiment in which all UEs can move to the same area; Figure 14 illustrates if power consumption is not an issue And there is no inactive BTS in the neighborhood of the UE that can be connected, another solution is to increase one embodiment of the transmission power at the BTS away from the UE cluster.

One solution to overcome many of the limitations of the prior art described above is one embodiment of a Decentralized Input Decentralized Output (DIDO) technique. The DIDO technology is described in the following patents and patent applications, the entireties of which are hereby incorporated by reference. These patents and applications are sometimes referred to herein as "related patents and applications".

U.S. Application Serial No. 13/475,598, entitled "Systems and Methods to Enhance Spatial Diversity in Distributed Input Distributed Output Systems."

U.S. Application Serial No. 13/464,648, entitled "System and Methods to Compensate for Doppler Effects in Distributed-Input Distributed Output Systems."

US Application No. 12/917,257 entitled "Systems And Methods To Coordinate Transmissions In Distributed Wireless Systems Via User Clustering"

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

U.S. Patent No. 8,170,081, entitled "System And Method For Adjusting DIDO Interference Cancellation Based On Signal Strength Measurements", issued May 1, 2012.

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

US Application 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"

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

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

US Application No. 12/802,938 entitled "System And Method For DIDO Precoding Interpolation In Multicarrier Systems"

U.S. Application No. 12/630,627 entitled "System and Method For Distributed Antenna Wireless Communications"

US Patent No. 7,599,420, entitled "System and Method for Distributed Input Distributed Output Wireless Communication", dated October 6, 2009; "System and Method for Distributed Input Distributed Output", December 15, 2009 US Patent No. 7,633,994 to Wireless Communication; US Patent No. 7,636,381 entitled "System and Method for Distributed Input Distributed Output Wireless", dated December 22, 2009; U.S. Patent No. 8,160,121 to "System and Method For Distributed Input-Distributed Output Wireless Communications"; US Patent No. 11/256,478, entitled "System and Method For Spatial-Multiplexed Tropospheric Scatter Communications"; US Patent entitled "System and Method for Distributed Input Distributed Output Wireless Communication", August 26, 2008 No. 7,418,053; U.S. Application Serial No. 10/817,731, entitled "System and Method For Enhancing Near Vertical Incidence Skywave ("NVIS") Communication Using Space-Time Coding.

In order to reduce the size and complexity of the present patent application, the disclosure of some of the related patents and applications is not explicitly set forth below. For a complete description of the disclosure, please refer to the relevant patents and applications.

System description

We describe a multi-user (MU) multi-antenna system (MAS) for wireless transmission that includes a wireless and/or wired backhaul for connecting multiple antennas. As depicted in FIG. 1, MU-MAS by a centralized processor 101, network user 102 and the N-terminal device UE1-UE4 to communicate wireless transceiver station 103 of the M components.

The centralized processor unit 101 receives different network content intended for different client devices (eg, video, webpage, video game, text, voice, etc. streamed from a web server or other network source), etc. -C5) N information streams . In the following, we use the term "information stream" to mean that a packet transmitted over the network can be demodulated or decoded into a separate stream according to a modulation/writing scheme or protocol to generate a certain voice, data or video. Any data of the content information is streamed. In one embodiment, the information stream is a sequence of bits carrying network content that can be demodulated or decoded into an independent stream.

The centralized processor 101 utilizes a precoding transform to combine the N information streams from the network content C1-C5 (according to a particular algorithm) into M bitstreams . The precoding transform can be linear (eg, zero forcing [22], block diagonalization [20-21], matrix inversion, etc.) or non-linear (eg, dirty paper encoding [11-13] or Tomlinson-Harashima precoding [14-15], mesh technology or format precoding [16-17], vector perturbation technique [18-19]). In the following, we use the term "bitstream" to refer to any sequence of bits that do not necessarily contain any useful information bits and therefore cannot be demodulated or decoded into separate streams to retrieve network content. In one embodiment of the invention, the bit stream is a composite baseband signal generated by a centralized processor and quantized relative to a given number of bits to be transmitted to one of the M transceiver stations 103.

In one embodiment, the MAS is a Decentralized Input Decentralized Output (DIDO) system as described in our prior patent application [0002-0018]. In this embodiment, the DIDO system consists of the following:

User Equipment (UE) 104 : The RF transceiver for the fixed or mobile client 104 receives the data stream from the DIDO backhaul via the downlink (DL) channel and transmits the data via the uplink (UL) channel to DIDO return trip

̇ Base Transceiver Station (BTS) 103: BTS 103 interfaces DIDO backhaul and wireless channels. The BTS of an embodiment is an access point 103 comprised of a DAC/ADC and a radio frequency (RF) chain that converts the baseband signal to RF. In some cases, the BTS is a simple RF transceiver equipped with a power amplifier/antenna, and the RF signal is carried to the BTS via an on-fiber RF technology as described in our prior patent application.

̇ Controller (CTR): CTR is a specific type of BTS 103 designed for certain dedicated features, such as training signals for time/frequency synchronization for BTS and/or UE, reception/transmission from/to The control information of the UE receives channel state information (CSI) or channel quality information from the UE. One or more CTR stations can be included in any DIDO system. When multiple CTRs are available, information to or from their stations is combined to increase diversity and improve link quality. In one embodiment, CSI is received from multiple CTRs via a maximum ratio combining (MRC) technique to improve CSI demodulation. In another embodiment, control information is transmitted from multiple CTRs via maximum ratio transmission (MRT) to improve the SNR at the receiver side. The scope of the invention is not limited to MRC or MRT, and any other diversity technique (such as antenna selection, etc.) may be used to improve the wireless link between the CTR and the UE.

̇ Centralized Processor (CP): The CP is a DIDO server 101 that interfaces to the Internet or other types of external networks and DIDO backhaul. In one embodiment, the CP calculates the DIDO baseband processing and sends the waveform to the decentralized BTS for DL transmission.

Base Station Network (BSN): The BSN is a network 102 that connects the CP 101 to a decentralized BTS 103 carrying information for the DL or UL channel. The BSN is a wired or wireless network or a combination of both. For example, the BSN is a DSL, cable, fiber optic network, or line of sight or non-line of sight wireless link. In addition, the BSN is a proprietary network, or a regional network, or the Internet.

2. Wireless and wired backhaul

Embodiments of the present invention describe systems and methods for practical BSN deployment via wireless or wired links (or a combination of both) in a DIDO system. In one embodiment, the BSN is comprised of a high speed wired link 205 of FIG. 2 that is interconnected by a plurality of routers or gateways 202 and interconnects the centralized processor 201 to 202 and interconnects the routers or gateways 202 to each other. Wired network. Wired link 205 carries a bit stream to be sent to all BTSs 204 connected to the same DIDO BSN. The router and gateway are connected to the switch or hub 203 via a wired link 206. The wired link 206 carries only the bit stream intended to connect to the BTS 204 of the same switch or hub 203. The BTS 204 simultaneously transmits the bit stream received from the centralized processor 201 via the DIDO wireless link in such a manner that each UE recovers and demodulates one of its own information streams.

Wired links 205 and 206 include various network technologies including, but not limited to, digital subscriber line (DSL), cable modem, fiber optic ring, T1 line, fiber-optic coaxial cable (HFC) network. Dedicated fiber typically has very large bandwidth and low latency (which may be less than one millisecond in a local area), but has a narrower deployment range than DSL and cable modems. Today, DSL and cable modem connections in the United States typically have a last dive between 10ms and 25ms, but are widely deployed.

The bit stream transmitted via the BSN consists of a baseband signal from the CP to the BTS. Assume that each composite sample of the baseband signal is quantized to 32 bits (ie, 16 bits for the real part and 16 bits for the imaginary part), and the BSN is 10M samples/second via the wireless DIDO link (also That is, the total bandwidth requirement for operating the BTS of 10 MHz bandwidth is 320 Mbps. In general, quantization of only 16 bits or less is sufficient to represent a baseband signal with negligible error (especially if compression techniques are used to reduce bandwidth requirements), thereby reducing BSN throughput requirements. Up to 160Mbps or less. In one embodiment of the invention, the DIDO system uses compression techniques to reduce the amount of throughput required on the BSN backhaul. In addition, DIDO technology has been shown to provide an order of magnitude increase in spectral efficiency relative to any existing wireless technology. Therefore, it is possible to relax the fundamental frequency throughput at the BTS from 10M samples/second to 5M samples/second or 1M samples/second while providing comparable or comparable via wireless link to any conventional wireless communication system. High per user throughput. Therefore, in a practical DIDO deployment, the throughput requirement at the BSN can be as low as 16 Mbps per BTS.

In another embodiment, when a wireless link is used between two BTSs, one BTS acts as a wirelessly redistributed bitstream to other remote BTS access points ( BTS-APs ) 308. Each remote BTS receives its dedicated bit stream from the BTS-AP and retransmits via the DIDO wireless link to act as a repeater ( BTS-RP ) 309. Note that the z-shaped single arrowed line in Figure 3 indicates the wireless transmission bit stream from the BTS to the UE via the DIDO link, while the straight double arrowed line indicates the point-to-point wireless transmission via the BSN backhaul.

Some examples of wireless links for BSN backhaul are commercially available WiFi bridges operating in the ISM 2.4, 5.8 or 24 GHz band [1-5], or wireless optics such as laser light transmission [6] Communication, or any other radio frequency (RF) or optical proprietary system that provides high-throughput low-latency wireless network connectivity. Note that all of the above systems can achieve reliable connection speeds from 100 Mbps up to 1 Gbps or greater, which is sufficient to achieve a high speed wireless link between the BTS-AP and the BTS-RP on the BSN.

In another embodiment, BTS-AP 408 to a plurality of streams BTS-RP 409 and BTS-RP 410 via a point to multipoint radio link retransmissions bits, as shown in FIG. 4. The BTS-AP uses the same radio resources (ie, the same time and the same frequency band) for all links to the BTS-RP, and by establishing a very narrow beam (via a strong directional antenna or antenna array using beamforming techniques) ) Avoid interference between links. Narrow beams can also be used at the BTS-RP to improve link quality and reduce interference from other adjacent locations. When the remote locations are too close to each other and the narrow beams are directed to the remote locations without interfering with each other, they may be in their BTS via different multiple access technologies (such as TDMA, FDMA, OFDMA or CDMA). - The same radio resource is shared between RPs.

To provide network services from BTS-AP to BTS-RP, the present invention uses point-to-point or point-to-multipoint line of sight (LOS) links. In another embodiment, the LOS may not be available and the link uses beamforming, MRT, MIMO, or other diversity techniques to improve link quality in non-LOS (NLOS) links.

Another way to extend the coverage area of the wireless backhaul is via the mesh network [5, 7-9]. Webpass [8] has deployed a utility mesh network in the San Francisco (CA) business district using Wi-Fi transceivers operating in the ISM band, which can achieve speeds from 45 Mbps up to 200 Mbps. As described above, these speeds will be sufficient to carry a bit stream from the CP to the BTS in a practical BSN deployment. In one embodiment of the invention, the DIDO system utilizes the mesh network [ 5 , 7-8] of Figure 5 to extend coverage to a plurality of BTSs dispersed over a wide area. Each loop of the mesh network contains one or more BTS-APs to guarantee a continuous connection to other BTS-RPs even in the event of a temporary or permanent network failure.

An example of a BSN deployment in the San Francisco (CA) business district is depicted in FIG . The circle indicates where you have access to fiber or other types of high-speed wired network connections. Some of these locations may be equipped with BTS-APs, or routers and switches using antennas 307 for point-to-point stream wireless transmission to other BTSs. The solid dots represent the BTS-RP 309, or routers and switches that use the antenna 307 to receive the bitstream and retransmit it via the DIDO wireless link. Note that the BTS-AP can also retransmit its own bit stream wirelessly via the DIDO link, thereby acting as a repeater.

In one embodiment of the invention, one or more of the highest BTS-APs in the BSN broadcast control information to all other DIDO BTSs. The control information consists of a training sequence or known pilot at a given frequency used to recover the time and frequency offset at the BTS. For example, the primary BTS-AP transmits a training sequence known by all other BTSs such that their BTSs can estimate time and frequency offsets and use time and frequency offsets for time and frequency synchronization. In this scenario, the BTS does not require any Global Positioning System (GPS) receivers to maintain time and frequency synchronization with each other.

I have observed that although the layout in Figure 6 looks similar to a typical cellular system (i.e., has a main tower that transmits wireless signals to multiple locations), its frame and functionality are fundamentally different. In fact, in contrast to the information stream in the cellular system, the BTS-AP sends a bit stream to the BTS-RP. In our invention, the bit stream is sent back via the BSN, while in the cellular system the information stream is sent from the tower to the user (i.e., after the backhaul, the last part of the communication link). Moreover, the link from the BTS-AP to each BTS-RP is a fixed point-to-point, meaning that it uses a strong directional antenna, so that interference to other BTS-RPs is removed, and link quality is improved. Honeycomb systems, on the other hand, transmit energy over the entire cell or part of a sector or sector (via beamforming) and by using different multiple access techniques (eg, TDMA, FDMA, OFDMA, CDMA, SDMA). Avoid interference across the user side.

When only one BTS-AP is insufficient to serve multiple BTS-RPs spread over a large area, additional BTS-APs can be used to establish other point-to-point/multipoint links to the BTS-RP. For example, Figure 7 shows two stations in a San Francisco business district with point-to-multipoint links. Note that any BTS-RP can also relay signals to other BTS-NPs as shown on the left side of the figure.

Figure 8 depicts an exemplary mesh network deployment in which nodes are dispersed around the San Francisco business district. Several key advantages of the mesh type architecture are:

̇Serial (serendipitous) deployment : BTS can be placed at any convenient place. For the BTS-AP, only the connection to the power supply and the connection to the high-speed wired network are required. The BTS-RP does not require a network connection because it can be built wirelessly and can be placed anywhere that leads to the roof. In contrast, in prior art wireless systems, such as cellular systems, BTSs are limited by their physical placement and physical barriers relative to each other, often resulting in expensive, inconvenient or unsightly placement, or if desired If the placement is not available, it will result in a loss of coverage.

̇ Better coverage : Since the BTS can be installed in an accidental manner, it is assumed that at least one BTS connected to the mesh network can be found to be practical from almost any location around the service area. Therefore, when a new BTS-RP is installed, there is a great chance that other BTS-RPs or BTS-APs will be found in the adjacent area to access the mesh network. Likewise, any UE at a given location can see at least one or more BTSs to deliver its information stream.

̇ Lower power consumption : Each BTS does not need to wirelessly transmit a bit stream to a remotely located BTS. In fact, in a mesh network, the BTS only contacts one or several BTSs in its neighborhood, thereby reducing transmission power requirements and producing significant improvements in power consumption.

较高 High robustness to network failures : In a mesh network, one or more BTS-APs are connected to the same loop, so that there is always a network connection, even if one or more BTS-APs are attributable to The same is true in the extreme case of a network failure or a temporary power outage.

In one embodiment of the invention, the BSN is an accidental network with nodes (e.g., BTS, BTS-AP or BTS-RP) installed at any convenient location. Evaluate the ease of installation of BTS in the network based on: 可用性 availability of high-speed, low-latency network or internet connectivity, whether wired, wireless, fiber-optic, or other connectivity; Whether the authorization to install the BTS in the location (eg, roof, pole, pole, or stone) is feasible, or if there are any restrictions imposed by the FCC emission limits; ̇ renting is cheap to specify the location where the BTS is installed. Network Department The CAPEX and OPEX are maintained at a minimum to gain one of the economic advantages of DIDO over the cellular system. This is achieved by installing many very inexpensive BTSs, with overall CAPEX and OPEX being much lower than the cellular towers required to cover the same service area.

Some embodiments discussed herein and in related patents and applications require: i) access to a wired network connection; ii) a power outlet. Removing these two requirements can significantly simplify the installation and maintenance of the BTS, making the DIDO network more contingent. As discussed above, it is possible to remove the first requirement by establishing a point-to-point/multipoint wireless link using BTS-AP and BTS-RP. In order to eliminate the second requirement, embodiments of the present invention provide two solutions: i) utilizing solar energy; ii) using wireless power transfer.

In one embodiment of the invention, the solar panel 901 is coupled to a charge controller 902 that charges the battery 903 (the image of the meter is for illustrative purposes only and is not a requirement for the charge controller), as shown in FIG. Show. The battery provides DC current to the BTS 905 via an inverter 904 that converts the battery voltage to a voltage defined by the specifications of the BTS. For example, if the BTS accepts an input voltage of 6V and the battery provides 12V, the inverter converts 12V to 6V. The BTS is equipped with an antenna 906 to transmit radio waves to the UE via a wireless DIDO link and receive radio waves from the UE. In addition, the BTS is connected to another antenna 907 that provides network connectivity via a point-to-point/multipoint wireless link. Note that antennas 906 and 907 can be tuned to the same frequency or to different frequencies, depending on the portion of the spectrum used for the two different types of links. For example, the DIDO link to antenna 906 can be designed to operate at VHF or UHF, while the point-to-point/multipoint link to antenna 907 can use the ISM band of the microwave (ie, 5.8 GHz for WiFi). . In one embodiment of the invention, their links are not limited to any particular operating frequency.

As an example, assume that the BTS draws 3 amps (A) of current at a 6V DC input voltage, with an efficiency of less than 10% (ie, considering the power loss in the circuit and the use of a Class A linear power amplifier, its efficiency is usually very low ) transmitting 1W via a wireless link. If the battery rated capacity is 60 Ah, the presently preferred embodiment will only discharge the battery to 50% (or 30 Ah) to maintain its life. Thus, when the BTS is continuously energized and operated at a radiant power of 1 W, it will take about 10 hours to discharge the battery to 50%. Typical commercially available solar panels operate at about 20% efficiency, yielding about 12 W/ft ² . Assuming a sufficient area to accommodate 5 ft ² of solar panels, the total power produced by solar panel 901 is 60 W. Since the battery voltage is typically 12V DC, the solar panel 901 provides 5A current to the battery via the charge controller. Therefore, the solar panel will take about 6 hours to recharge the battery from 50% to 100% fully charged. This is a typical example of a self-contained system in which the charging rate is faster than the discharge rate. Note that for nighttime operation, short charging rates and long discharge rates are particularly convenient when the solar panels are not active due to lack of sunlight. In another embodiment, multiple batteries and a switch are used to switch between different batteries, allowing for independent charging/discharging cycles throughout the day and maintaining a stable power supply during night time.

In areas characterized by insufficient sunlight (for example, in rainy and cloudy places or locations close to the Arctic and Antarctic, shaded areas, etc. during periods of short duration during the day), solar panels may not be A practical solution for BTS power supply. An alternative solution is wireless power transfer. Another embodiment of the present invention utilizes the chirped rectifier diode antenna 1001 of FIG. 10 to provide DC current to the battery 1003 via the charge controller 1002. Wireless power is transmitted to the 矽rectifying diode antenna 1001 via a strong directional antenna at different locations. In one embodiment, the wireless power transmitter is one of a strong directional antenna or a plurality of BTS-APs that are used to form a very narrow beam that is aimed at the position of the rectifying diode antenna 1001. The rectifying diode antenna 1001 itself is equipped with a strong directional antenna to increase the amount of received power.

In another embodiment, the silicon rectifying diode 1001 and an antenna for point / multipoint wireless link antenna 1007 to form the receiver 1107 shown in FIG. 11. This uses the same antenna 1107 to demodulate the digital content from the wireless network and store the power for feeding to the battery and thus to the small design of the BTS.

3. Reconfigurable BTS configuration

We have described systems and methods for wireless backhaul that provide network connectivity to all BTSs in the same BSN. Next, we describe a system and method for reconfiguring a network topology based on UE dispersion. In a recent report by Morgan Stanley [10], it has been shown that the traffic in current cellular systems is very uneven: in a typical cellular network, only 20% of base stations carry 80% of the information services. This effect is due to the high concentration of wireless users in densely populated metropolitan areas. In these areas, data congestion occurs when multiple users attempt to simultaneously access the cellular network during peak hours of the day, resulting in disconnection, limited connection speed, and poor coverage.

A key advantage of DIDO is its ability to dynamically reconfigure the network to accommodate the ever-changing spatial dispersion of users in a certain area over time and the variable dispersion of traffic. 12 shows a typical DIDO network consisting of a transmission bit stream streamed to the BTS 1201 of the UE 1203 and an inactive BTS 1202 connected to the BSN but transmitting no data over the radio link. The circle around the BTS in effect indicates its coverage area. In this scenario, the UE is evenly dispersed around a given area and the CP has activated all BTSs in the vicinity of the UE to ensure good coverage.

However, the dispersion of the UE may change during certain times of the day. For example, in the case of public events, all UE may move in the same region as depicted in the FIG. 13. In this case, the CP recognizes the change in UE dispersion and starts the BTS closer to the UE while setting the other BTSs to be inactive. In one embodiment, the CP determines the path loss from each BTS to each UE based on CSI feedback or any training or other control information sent from the UE to the BTS via the uplink radio channel. Note that the number of active BTSs remains constant as the UE configuration changes over time to ensure that there is sufficient freedom on the wireless link to establish parallel non-interfering channels to all UEs. In addition, setting some of the active BTSs to be in use is a way to conserve power and keep the computational complexity at the CP constant. In another embodiment, when the UE is dispersed, the active BTS is not set to be inactive, thereby ensuring better coverage at the expense of more power consumption at the CP and higher computational complexity.

If power consumption is not a problem and can be inactive in the open BTS does not exist in the neighborhood of the UE, then the other solution-based solutions to increase the transmission power at the BTS in the UE away from the cluster, as shown in FIG. 14. Increasing the transmission power creates a more interference pattern across the BTS that is utilized by the DIDO precoder to establish a data stream that does not interfere with each other.

4. References

[1] Ubuquiti, "airMAX", http://www.ubnt.com/airmax

[2] Ubuquiti, "airFiber", http://www.ubnt.com/airfiber

[3] MikroTik, "Routerboard", http://routerboard.com/

[4] Ruckus wireless, "Long-range 802.11n Wi-Fi point-to-point/multipoint backhaul", http://www.ruckuswireless.com/products/zoneflex-outdoor/7731

[5] DigitalAir wireless, "Outdoor wireless", http://www.digitalairwireless.com/outdoor-wireless-networks.html

[6] DigitalAir wireless, "GeoDesy laser links 1.25Gbps full duplex", http://www.digitalairwireless.com/outdoor-wireless-networks/point-to-point-wireless/laser-fso-links/geodesy-fso- Laser-links.html

[7] Netsukuku, http://netsukuku.freaknet.org/

[8] Webpass, "Buildings online" http://www.webpass.net/buildings? City=san+francisco&column=address&order=asc

[9] BelAir Networks, "Small cells" http://www.belairnetworks.com/sites/default/files/WP_SmallCells.pdf

[10] Morgan Stanley's "Mobile data wave: who dares to invest, wins" on June 13, 2012

[11] May 1983, IEEE Transactions on Information Theory , Vol. 29, No. 3, pp. 439-441, M. Costa, "Writing on dirty paper".

[12] July 2003, IEEE Trans. Info. Th., Vol. 49, pp. 1691 to 1706, G. Caire and S. Shamai, "On the achievable throughput of a multiantenna Gaussian broadcast channel".

[13] May 2005, IEEE Trans. on Information Theory, Vol. 51, pp. 1783 to 1794, Nihar Jindal and Andrea Goldsmith, "Dirty Paper Coding vs. TDMA for MIMO Broadcast Channels"

[14] March 1971, Electronics Letters , pp. 138-139, M. Tomlinson, "New automatic equalizer employing modulo arithmetic".

[15] Transactions of the Institute of Electronic , H. Miyakawa and H. Harashima, "A method of code conversion for digital communication channels with intersymbol interference"

[16] November 2000, Honolulu, Hawaii , Proceedings of International Symposium on Information Theory , U. Erez, S. Shamai (Shitz) and R. Zamir, "Capacity and lattice-strategies for cancelling known interference".

[17] 2001, IEEE Globecom, vol. 2, pp. 1344 to 1348, W. Yu and J. M. Cioffi, "Trellis Precoding for the Broadcast Channel"

[18] January 2005, IEEE Trans. On Communications, Vol. 53, No. 1, pp. 195-202, BM Hochwald, CB Peel and AL Swindlehurst "A Vector-Perturbation Technique for Near-Capacity Multiantenna Multiuser Communication - Part I: Channel Inversion and Regularization"

[19] March 2005, IEEE Trans. On Communications, Vol. 53, No. 3, pp. 537-544, B. M. Hochwald, C. B. Peel and A. L. "A Vector-Perturbation Technique for Near-Capacity Multiantenna Multiuser Communication - Part II: Perturbation" by Swindlehurst

[20] July 2003, IEEE Trans. Wireless Comm., Vol. 2, pp. 773-786, K. K. Wong, R. D. Murch and K. B. Letaief, "A joint channel diagonalization for multiuser MIMO antenna systems";

[21] March 2007, IEEE Trans. on Signal Processing , Vol. 55, No. 3, pp. 1159 to 1171, R. Chen, RW Heath, Jr. and JG Andrews, Transmit Selection Diversity for Unitary Precoded Multiuser Spatial Multiplexing Systems with Linear Receivers".

[22] RA Monziano and TW Miller, Introduction to Adaptive Arrays ( New York: Wiley, 1980).

101‧‧‧Centralized processor

102‧‧‧Network

103‧‧‧ transceiver station

104‧‧‧User Equipment (UE)

Claims (17)

A multi-user (MU) multi-antenna system (MAS) comprising: one or more centralized units communicatively coupled to a plurality of decentralized transceiver stations via a network; the network routing wired or wireless links or One of the two is combined, the network is used as a backhaul communication channel; the centralized unit converts N information streams into M bit streams, each bit stream is some or all N information strings a combination of streams; the M bitstreams are sent to the decentralized transceiver stations via the network; the decentralized transceiver stations simultaneously transmit the bitstreams to at least one client device via a wireless link And causing at least one client device to receive at least one of the original N information streams. The system of claim 1, wherein the MU-MAS is a distributed input distributed output (DIDO) system, the centralized unit includes a centralized processor (CP), and the distributed transceiver station includes a base transceiver station ( BTS), the network includes a base station network (BSN), which includes user equipment (UE). A system as claimed in claim 2, wherein the wireless or wired BSN interconnects a plurality of BTS or controller (CTR) stations. The system of claim 2, wherein the wireless or wired BSN interconnects one or more BTS access points (BTS-APs) or routers or switches to one or more BTS repeaters (BTS-RPs) or routers Or a switch. A system as claimed in claim 1, wherein the wireless link consists of a point-to-point or point-to-multipoint line-of-sight link. A system as claimed in claim 5, wherein the wireless link uses a commercially available or proprietary system operating at radio frequency or via optical communication. A system as claimed in claim 1, wherein the wireless link consists of a point-to-point or point-to-multipoint non-line of sight link. A system as claimed in claim 7, wherein the wireless link uses beamforming, MRT, MIMO or other diversity techniques to improve link quality. The system of claim 2, wherein the BSN consists of a mesh network. A system as claimed in claim 9, wherein the one or more BTSs are connected to the same mesh network such that the BSN maintains a connection with all other BTSs in the event of a failure of one or more BTSs. A system as claimed in claim 1, wherein the compression technique is for reducing the amount of throughput required to transmit the bit stream over the network. A system as claimed in claim 2, wherein the BTS broadcasts control information to some or all of the BTSs of the DIDO network to allow time and frequency synchronization of their BTSs. A system as claimed in claim 2, wherein the system is accidental and is designed such that the BTS is located in either location. A system as claimed in claim 3, wherein the plurality of CTR stations use MRC, MRT or any other diversity technique to improve transmission and reception via their wireless links. The system of claim 2, wherein the BTS is powered by a solar panel. The system of claim 2, wherein the BTS is powered using wireless power transfer. The system of claim 2, wherein the CP identifies a change in the dispersion of the UEs over a particular area or a change in the services of the UEs over time, and provides the best link to the devices by dynamically initiating The BTS of the UE reconfigures the network.