Device, system, and method of wireless communication of base stations

Device, system and method of wireless communication of base stations. In some demonstrative embodiments a method may include, for example, transmitting a downlink transmission over a frequency band from a first base station during a first time period; and receiving at a second base station an uplink transmission over the frequency band during a second time period at least partially overlapping the first time period. Other embodiments are described and claimed.

BACKGROUND

In cellular networks, a Radio Network Controller (RNC) may control a plurality of Base Stations (BSs). An upper Medium Access Control (MAC) layer may run at the RNC, and a lower layer MAC and a physical (PHY) layer may run at the base stations. The RNC may provide a base station with downlink data to be transmitted to one or more mobile communication devices associated with the base station The RNC may be connected to the base stations via wired links, e.g., having high bandwidth.

According to a conventional frame allocation all co-channel base stations may send downlink data simultaneously over the same frequency band, and receive uplink data simultaneously over the same frequency band.

In order to improve performance, data received from multiple base stations may be sent to the RNC, which may perform joint Multiple-Input-Multiple-Output (MIMO) detection This may require large bandwidth and increase the complexity of the RNC.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of some embodiments. However, it will be understood by persons of ordinary skill in the art that embodiments of the invention may be practiced without these specific details In other instances, well-known methods, procedures, components, units and/or circuits have not been described in detail so as not to obscure the discussion.

Some embodiments may be used in conjunction with various devices and systems, for example, a Personal Computer (PC), a desktop computer, a mobile computer, a laptop computer, a notebook computer, a tablet computer, a server computer, a handheld computer, a handheld device, a Personal Digital Assistant (PDA) device, a handheld PDA device, an on-board device, an oft-board device, a hybrid device, a vehicular device, a non-vehicular device, a mobile or portable device, a non-mobile or non-portable device, a wireless communication station, a wireless communication device, a wireless Access Point (AP), a wired or wireless router, a wired or wireless modem, a wired or wireless network, a Local Area Network (LAN), a Wireless LAN (WLAN), a Metropolitan Area Network (MAN), a Wireless MAN (WMAN), a Wide Area Network (WAN), a Wireless WAN (WWAN), a Personal Area Network (PAN), a Wireless PAN (WPAN), One way and/or two-way radio communication systems, cellular radiotelephone communication systems, a cellular telephone, a wireless telephone, a Personal Communication Systems (PCS) device, a PDA device which incorporates a wireless communication device, a mobile or portable Global Positioning System (GPS) device, a device which incorporates a GPS receiver or transceiver or chip, a device which incorporates an RFID element or chip, a Multiple Input Multiple Output (MIMO) transceiver or device, a wired or wireless handheld device (e.g., Blackberry, Palm Treo), a Wireless Application Protocol (WAP) device, or the like Types of WLAN and/or WMAN communication systems intended to be within the scope of the present invention include, although are not limited to, WLAN and/or WMAN communication systems as described by “IEEE-Std 802.16, 2004 Edition, Air Interface for Fixed Broadband Wireless Access Systems” standard (“the 802.16 standard”), and more particularly in “IEEE-Std 802.16e, 2005 Edition, Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands”, “IEEE-Std 802.16m, Air Interface for Fixed Broadband Wireless Access Systems—Advanced Air Interface”, and the like, and/or future versions and/or derivatives and/or Long Term Evolution (LTE) of the above standards.

Some embodiments may be used in conjunction with one or more types of wireless communication signals and/or systems, for example, Radio Frequency (RE), Infra Red (IR), Frequency-Division Multiplexing (FDM), Orthogonal FDM (OFDM), Time-Division Multiplexing (TDM), Time-Division Multiple Access (TDMA), Extended TDMA (E-TDMA), General Packet Radio Service (GPRS), extended GPRS, Code-Division Multiple Access (CDMA), Wideband CDMA (WCDMA), CDMA 2000, Multi-Carrier Modulation (MDM), Discrete Multi-Tone (DMT), Bluetooth, Global Positioning System (GPS), Wi-Fi, Wi-Max, ZigBee™, WiHD, Ultra-Wideband (UWB), Global System for Mobile communication (GSM), Enhanced Data GSM Environment (EDGE), 2 G, 2.5 G, 3 G, 3.5 G, or the like. Some embodiments may be used in various other devices, systems and/or networks.

FIG. 1schematically illustrates a block diagram of a wireless communication system100in accordance with some demonstrative embodiments System100may include, for example, a plurality of base stations (BSs) capable of communicating with a plurality of mobile communication devices. For example, system100may include a first BS104capable of communicating with at least one mobile device110; and a second BS106capable of communicating with at least one mobile device108. Devices108and/or110may be or may include, for example, a mobile phone, a cellular phone, a handheld device, a computing device, a computer; a mobile computer, a portable computer, a laptop computer, a notebook computer, a tablet computer, a network of multiple inter-connected devices, a handheld computer, a handheld device, a PDA device, a handheld PDA device, a vehicular device, a non-vehicular device, a mobile or portable device, or the like. Devices108and/or110may include one or more antennas118, and/or122, respectively; and/or base stations104and/or106may include one or more antennas116and/or120, respectively. Although embodiments of the invention are not limited in this respect, types of antennae that may be used for antennas116,118,120and/or122may include but are not limited to internal antenna, dipole antenna, omni-directional antenna, a monopole antenna, an end fed antenna, a circularly polarized antenna, a micro-strip antenna, a diversity antenna and the like.

In some demonstrative embodiments, BS104, BS106, mobile device108and/or mobile device110may include a controller132, a receiver128, and/or a transmitter130. For example, transmitter130may transmit via antenna116wireless RF signals, blocks, frames, transmission streams, packets, messages and/or data, e.g., to mobile device110; and/or receiver128may receive via antenna116wireless RF signals, blocks, frames, transmission streams, packets, messages and/or data, e.g., from mobile device110. Transmitter130may include, for example, any suitable RE transmitter; and/or receiver128may include any suitable RF receiver. Optionally, transmitter130and receiver128may be implemented using a transceiver, a transmitter-receiver, or other suitable component. In some embodiments, controller132, transmitter130and/or receiver128may be implemented as part of a Medium Access Control (MAC) layer, a physical (PHY) layer of BS104, and/or any other suitable communication layer or configuration.

In some demonstrative embodiments, base stations104and106may optionally be associated with a common Radio Network Controller (RNC)102. For example, BS104may communicate with RNC102via a suitable link, e.g., a wired or wireless link112; and/or BS106may communicate with RNC102via a suitable link, e.g., a wired or wireless link114. In one example, a high layer MAC may be run by RNC102, and a low layer MAC and/or a PHY layer may be run by base stations104and106. RNC102may provide base stations104and106, e.g., via links112and114, respectively, with downlink data to be transmitted to mobile communication devices110and108, respectively In other embodiments, base stations104and106may be associated with any other suitable communication device, and/or may communicate with one another directly, e.g., without using RNC102.

In some demonstrative embodiments, information regarding transmissions from and/or to base stations104and/or106may be provided to base stations104and/or106, for example, via links112and114in order, for example, to mitigate co-channel interference, which may result from the uplink and/or downlink wireless transmissions between BS104and mobile device110, and the uplink and/or downlink wireless transmissions between BS106and mobile device108, e.g., as described below.

In some demonstrative embodiments, BS104and BS106may include co-channel base stations capable of communicating over one or more common frequency bands For example, BS106may include base stations of interfering cells, which may contribute to one another relatively strong interference.

In some demonstrative embodiments, BS104may transmit a downlink transmission over a frequency band, denoted f, to mobile device110during a first time period, which may at least partially overlap a second time period, during which BS106may receive an uplink transmission from mobile device108over the same frequency band f, e.g., as described in detail below BS104may receive an uplink transmission, edge, from mobile device110, over a frequency band f′ during a third time period at least partially overlapping a fourth time period, during which BS106is to transmit a downlink transmission over the same frequency band f′, e.g., to mobile device108, e.g., as described below. The frequency bands f and f′ may include the same frequency band, e.g., if the transmissions include Time Division Duplexing (TDD) transmissions; or different frequency bands, e.g., if the transmissions include Frequency Division Duplexing (FDD) transmissions, as described below.

Reference is also made toFIGS. 2A and 2Bwhich schematically illustrate a TDD allocation scheme210, and a FDD transmission allocation scheme220in accordance with some demonstrative embodiments. Although embodiments of the invention are not limited in this respect in some demonstrative embodiments schemes210and/or220may be implemented by system100, e.g., by BS104, BS106, mobile device108, and/or mobile device110.

In some demonstrative embodiments, scheme210may allocate a transmission period201to be used for transmissions over a common frequency band, denoted f1, between a plurality of base stations and a plurality of mobile devices. Transmission period201may include a first time period206allocated to a downlink transmission from a first base station to a first mobile device, e.g., from BS104to mobile device110; a second time period202allocated to an uplink transmission from a second mobile device to a second base station, e.g., from mobile device108to BS106; a third time period208allocated to an uplink transmission from the first mobile device to the first base station, e.g., from mobile device110to BS104; and a fourth time period204allocated to a downlink transmission from the second base station to the second mobile device, e.g., from BS106to mobile device108. In one example, time periods202and/or208may be shorter than time periods206and/or204, respectively.

In some demonstrative embodiments, time period206may at least partially overlap time period202; and/or time period208may at least partially overlap time period204. In one example, there may be a maximal overlap between time period202and time period206; and/or a maximal overlap between time period208and time period204. For example, time period202may be substantially entirely included within time period206; and/or time period208may be substantially entirely included within time period204.

In some demonstrative embodiments, scheme220may allocate a transmission period221to be used for transmissions over a plurality of frequency bands, e.g., including first and second frequencies, denoted f2and f3, respectively, between a plurality of base stations and a plurality of mobile devices. Scheme220may allocate, for example, an uplink transmission to a first BS and a downlink from a second base station over a common frequency band during substantially overlapping time periods. For example, transmission period221may include a first time period222allocated to a downlink transmission from a first base station to a first mobile device over the frequency band f2, e.g., from BS104to mobile device110; a second time period226allocated to an uplink transmission from a second mobile device to a second base station over the frequency band f2, e.g., from mobile device108to BS106; a third time period224allocated to an uplink transmission from the first mobile device to the first base station over the frequency band f3, e.g., from mobile device110to BS104; and a fourth time period228allocated to a downlink transmission from the second base station to the second mobile device over the frequency band f3, e.g., from BS106to mobile device108. In one example, time periods222,224,226and/or228may have substantially the same length.

In some demonstrative embodiments, time period222may at least partially overlap time period226; and/or time period224may at least partially overlap time period228. In one example, there may be a maximal overlap between time period222and time period226; and/or a maximal overlap between time period224and time period228. For example, time periods222,224,226, and228may overlap.

In some demonstrative embodiments a first interference to a first mobile device receiving a downlink transmission from the first BS may result from the uplink transmission of a second mobile device to the second BS, e.g., in accordance with transmission allocation schemes210and220. The first interference may be much weaker than a second interference, which may result from a downlink transmission from the second BS to the second mobile device, e.g., if a conventional transmission scheme is implemented. For example, a transmit power of a BS may be about 16 dB higher than a transmit power of a mobile device. The first and second mobile devices may have relatively low antenna mountings compared, for example, to antenna mountings of the first and second base stations. Accordingly, the first interference may be weaker than the second interference, since a path loss between the first and second mobile devices may be higher than a path loss between the first and second base stations, and/or the between the second BS and the first mobile device.

Referring back toFIG. 1, in some demonstrative embodiments, BS106may receive information corresponding to the downlink transmission of BS104, e.g., the downlink transmission of BS104overlapping with the uplink transmission of mobile device108, for example, before BS106receives the uplink transmission of mobile device108; and/or BS104may receive information corresponding to the downlink transmission of BS106, e.g., the downlink transmission of BS106overlapping with the uplink transmission of mobile device110, for example, before BS104receives the uplink transmission of mobile device110, e.g., as described below.

In some demonstrative embodiments, BS104may receive from RNC102data of a packet of the downlink transmission of BS106, e.g., the downlink transmission of time period of204(FIG. 2) that overlaps with time period208(FIG. 2), or the frequency band of time period228(FIG. 2) that overlaps with frequency band224(FIG. 2); and receive from BS106packet forming information of the packet of the downlink transmission of BS106, e.g., as described below. BS106may receive from RNC102data of a packet of the downlink transmission of BS104, e.g., the downlink transmission of time period206(FIG. 2) that overlaps with time period202(FIG. 2), or the frequency band of time period222(FIG. 2) that overlaps with frequency band226(FIG. 2); and receive from BS104packet forming information of the packet of the downlink transmission of BS104, e.g., as described below. The packet forming information of the packet may include, for example, information related to a modulation type, a forward error correction coding type, a space-time coding type, one or more modulation parameters, one or more control signals, resource allocation of the packet, and/or any other suitable information Alternatively, BS106may directly receive, e.g., from RNC102or BS104, symbols in the downlink transmission from BS104overlapping the uplink transmission of mobile device108. Accordingly, BS106may not need to reconstruct the transmitted signal of BS104using the information of both data and packet forming.

In some demonstrative embodiments, BS104may detect the uplink transmission to BS104based on the information corresponding to the downlink transmission of BS106; and/or BS106may detect the uplink transmission to BS106based on the information corresponding to the downlink transmission of BS104, e.g., as described below.

In some demonstrative embodiments, RNC102may provide BS104with data of the packet of the downlink transmission of BS106via link112; and/or provide BS106with data of the packet of the downlink transmission of BS104via link114.

In some demonstrative embodiments, BS104may determine the downlink transmission of BS106based on the information corresponding to the downlink transmission of BS106; and/or BS106may determine the downlink transmission of BS104based on the information corresponding to the downlink transmission of BS104, using any suitable estimation, detection, and/or interference mitigation method or algorithm, e.g., as described below.

In some demonstrative embodiments, BS104may estimate an interfering channel response corresponding to the downlink transmission of BS106based on the determined downlink transmission of BS106; and/or BS106may estimate an interfering channel response corresponding to the downlink transmission of BS104based on the determined downlink transmission of BS104, eggs, as described below.

In some demonstrative embodiments, BS104may detect the uplink transmission to BS104during the uplink time period, for example, by reconstructing a received signal resulting from the downlink transmission of BS106, and subtracting the reconstructed signal from a transmission received during the uplink time period, e.g., as described below.

In some demonstrative embodiments, a first BS, denoted A, e.g., one of base stations104and106, may use downlink data transmitted from a second BS, denoted B, e.g., another of base stations104and106, as channel training symbols to estimate an interfering channel of the BS B, and to cancel an interference from the BS B, while receiving uplink data from one or more mobile devices associated with the BS A, e.g., as described below. Canceling at the BS A the interference from the BS B may result, for example, in an improvement in network performance, e.g., an improvement of more than 20% in terms of spectrum efficiency. It is noted that an interference from a first mobile device associated with the BS A to a second mobile device associated with the BS B may be lower than the interference between the transmissions of the base stations A and B since, for example, a path loss between the first and second mobile devices is much higher than a path loss between the base stations A and B.

In some demonstrative embodiments, any suitable interference mitigation scheme or method may be implemented to reduce or cancel an interference of a signal from the BS B (“the interfering signal”) to an uplink signal intended for BS A (“the uplink signal”). In one example, the BS A may obtain some data contained in the interfering signal, denoted xb, before receiving the uplink signal, denoted xa, A channel response, denoted hb, of an interfering channel between the base stations A and B may be estimated by treating all the known data in the interfering signal as training pilots, and treating the uplink signal as noise. After estimating the channel response hb, the interfering signal may be reconstructed, for example, by applying the estimated channel response hbto the known interfering signal xb. The reconstructed interfering signal, denoted rb, may be subtracted from a received signal ra+rb, wherein radenotes the uplink signal as received by BS A. An interference-canceled signal corresponding to the signal xamay then be detected using any suitable detection method. It is noted that the mitigation method described above may not require synchronization of frequency and/or phase between the uplink signal and the interfering signal. Additionally or alternatively, the uplink and interfering signals may have different modulation types, e.g., CDMA and OFDMA.

In some demonstrative embodiments, the data xband one or more modulation parameters of the interfering signal may be provided, egg, via links112and114connecting the base stations A and B to common RNC102, e.g., as described above. The BS A may determine the interfering signal of the BS B using the data xband modulation parameters to perform interference cancellation, e.g., as described above. It is noted that a bandwidth required for sending the data from the RNC to the BS A may be much lower than a bandwidth required for sending quantized samples of the uplink signal received by the BS A to the RNC. The RNC may have substantially all of the data xbexcept, for example, for one or more control signals, e.g., including transmission power control, hybrid automatic repeat request (H-ARQ), and/or modulation parameters (“the additional data”). Accordingly, the BS B may provide the BS A with the additional data, e.g., one frame before the BS B transmits the interfering signal. In other embodiments, the additional data may be provided to BS A at or after the uplink signal is received by BS A, for example, if BS A is capable of storing or buffering the uplink signal.

In some demonstrative embodiments, a relatively high level of accuracy may achieved in the channel estimation of the interfering channel since, for example, the data xbis known, and the whole interfering signal may be used as channel training symbols, e.g., as described above. The density of training symbol may increases by a factor of about eight, e.g., in Wi-Max transmissions. Additionally, both the interfering and receiving stations include base stations, which may have a Line Of Sight (LOS) condition. This may reduce a number of channels taps required for the channel estimation and may improve the estimation accuracy for the same amount of data samples. Additionally, both the interfering station and the receiving station include static base stations. Therefore, the receiving BS may improve the estimation accuracy by averaging over time.

FIGS. 3A and 3Bschematically illustrate a first transmit/receive allocation 310 and a second transmit/receive allocation 320, for a 1×3×3 Frequency Reuse Scheme (FRS) in accordance with some demonstrative embodiments of the invention. Although embodiments of the invention are not limited in this respect in some demonstrative embodiments allocations 310 and/or 320 may be implemented by system100(FIG. 1), e.g., by BS104(FIG. 1), BS106(FIG. 1), mobile device108(FIG. 1), and/or mobile device110(FIG. 1). Allocations 310 and 320 include nineteen cells each having the same FRS. Each of the cells may have three sectors, wherein each of the three sectors employs a distinct frequency. As shown inFIGS. 3A and 3B, a relatively strong interference from a transmit cell302may be canceled by a center cell304.

The following table includes simulation results of downlink and uplink spectrum efficiency of a center cell in a 19-cell network for a conventional allocation scheme, allocation scheme 310 and allocation scheme 320. The simulation was carried out for a system including base stations having two transmit and receive antennas, and mobile devices having one transmit antenna and two receive antennas. A downlink and uplink time ratio of 1:1 was used for simplicity.

Reference is made toFIG. 4, which schematically illustrates a flow chart of a method of wireless communication in accordance with some demonstrative embodiments of the invention. Although embodiments of the invention are not limited in this respect, in some demonstrative embodiments one or more operations of the method ofFIG. 4may be implemented by system100(FIG. 1), e.g., by BS104(FIG. 1), BS106(FIG. 1), mobile device108(FIG. 1), and/or mobile device110(FIG. 1).

As indicated at block410, the method may include transmitting a downlink transmission from a first BS over a frequency band during a first time period at least partially overlapping a second time period during which an uplink transmission is to be received at a second BS over the same frequency band. For example, the first and second base stations may implement the allocation scheme ofFIG. 2Aor2B. The first and second base stations may include, for example, co-channel base-stations associated with a common RNC, e.g., as described above.

As indicated at block412, the method may include receiving at the second BS information corresponding to the downlink transmission. For example, the second BS may receive the information corresponding to the downlink transmission before processing the overlapping part of the received signal of the second time period, e.g., as described above.

As indicated at block414, receiving the information corresponding to the downlink transmission may include receiving data of a packet of the downlink transmission, e.g., from the RNC and/or the first BS. For example, the RNC may transmit the data of the downlink transmission to the second BS via a link, e.g., as described above.

As indicated at block416, receiving the information corresponding to the downlink transmission may include receiving from the first base station packet forming information of the packet. For example, the first BS may transmit to the second BS the packet forming information, e.g., as described above.

As indicated at block418, the method may also include detecting the uplink transmission at the second BS based on the information corresponding to the downlink transmission.

As indicated at block420, detecting the uplink transmission may include determining an interfering signal of the downlink transmission. For example, the second BS may determine the interfering signal using the information corresponding to the downlink transmission, e.g., as described above.

As indicated at block422, detecting the uplink transmission may also include estimating an interfering channel of the downlink transmission. For example, the second BS may estimate the channel response of the interfering channel based on the determined interfering signal, e.g., as described above.

As indicated at block424, detecting the uplink transmission may also include reconstructing the interfering signal. For example, the second BS may reconstruct the interfering signal based on the channel response of the interfering channel, e.g., as described above.

As indicated at block426, detecting the uplink transmission may also include detecting uplink data of the uplink transmission. For example, the second BS may subtract the reconstructed interference signal from the received uplink transmission, e.g., as described above.

As indicated at block428, the method may also include receiving an uplink transmission at the first base station during a third time period at least partially overlapping a fourth time period, during which the second base station is to transmit a downlink transmission. For example, the first and second base stations may implement the allocation scheme ofFIG. 2Aor2B.

Other suitable operations may be used, and other suitable orders of operation may be used.

Some embodiments, for example, may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment including both hardware and software elements. Some embodiments may be implemented in software, which includes but is not limited to firmware, resident software, microcode, or the like.

Furthermore, some embodiments may take the form of a computer program product accessible from a computer-usable or computer-readable medium providing program code for use by or in connection with a computer or any instruction execution system. For example, a computer-usable or computer-readable medium may be or may include any apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.

In some embodiments, the medium may be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. Some demonstrative examples of a computer-readable medium may include a semiconductor or solid-state memory, magnetic tape, a removable computer diskette, a RAM, a ROM, a rigid magnetic disk, and an optical disk Some demonstrative examples of optical disks include CD-ROM, CD-R/W, and DVD.

In some embodiments, a data processing system suitable for storing and/or executing program code may include at least one processor coupled directly or indirectly to memory elements, for example, through a system bus. The memory elements may include, for example, local memory employed during actual execution of the program code, bulk storage, and cache memories which may provide temporary storage of at least some program code in order to reduce the number of times code must be retrieved from bulk storage during execution.

In some embodiments, input/output or I/O devices (including but not limited to keyboards, displays, pointing devices, etch) may be coupled to the system either directly or through intervening I/O controllers. In some embodiments, network adapters may be coupled to the system to enable the data processing system to become coupled to other data processing systems or remote printers or storage devices, for example, through intervening private or public networks. In some embodiments, modems, cable modems and Ethernet cards are demonstrative examples of types of network adapters Other suitable components may be used.