Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
  • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
  • H04B7/0491—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas using two or more sectors, i.e. sector diversity
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
  • H04B7/022—Site diversity; Macro-diversity
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
  • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
  • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
  • H04B7/0686—Hybrid systems, i.e. switching and simultaneous transmission
  • H04B7/0691—Hybrid systems, i.e. switching and simultaneous transmission using subgroups of transmit antennas
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
  • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
  • H04B7/08—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station
  • H04B7/0837—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the receiving station using pre-detection combining
  • H04B7/0842—Weighted combining
  • H04B7/0848—Joint weighting
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
  • H04L1/0002—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/02—Arrangements for detecting or preventing errors in the information received by diversity reception
  • H04L1/06—Arrangements for detecting or preventing errors in the information received by diversity reception using space diversity
  • H04L1/0618—Space-time coding
  • H04L1/0625—Transmitter arrangements
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/02—Arrangements for detecting or preventing errors in the information received by diversity reception
  • H04L1/06—Arrangements for detecting or preventing errors in the information received by diversity reception using space diversity
  • H04L1/0618—Space-time coding
  • H04L1/0637—Properties of the code
  • H04L1/0656—Cyclotomic systems, e.g. Bell Labs Layered Space-Time [BLAST]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L27/00—Modulated-carrier systems
  • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
  • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
  • H04L27/3488—Multiresolution systems
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04B—TRANSMISSION
  • H04B7/00—Radio transmission systems, i.e. using radiation field
  • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
  • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
  • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
  • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
  • H04B7/0667—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of delayed versions of same signal

Definitions

• the present invention relates generally to telecommunications, and, more specifically, to methods, apparatus, and articles of manufacture for broadcasting and multicasting from a cellular radio network.
• a modern communication system is expected to provide reliable data transmission for a variety of applications, including voice and data applications.
• known communication systems are based on frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), and perhaps other multiple access communication schemes.
• FDMA frequency division multiple access
• TDMA time division multiple access
• CDMA code division multiple access
• a CDMA system may be designed to support one or more CDMA standards, such as (1) the "TIA/EIA-95 Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System” (this standard with its enhanced revisions A and B may be referred to as the "IS-95 standard”), (2) the “TIA/EIA-98-C Recommended Minimum Standard for Dual-Mode Wideband Spread Spectrum Cellular Mobile Station,” also known as the "IS-98 standard," (3) the standard sponsored by a consortium named “3rd Generation Partnership Project” (3GPP) and embodied in a set of documents including documents known as 3G TS 25.211, 3G TS 25.212, 3G TS 25.213, and 3G TS 25.214 (the "W-CDMA standard”), (4) the standard sponsored by a consortium named “3rd Generation Partnership Project 2" (3GPP2) and embodied in a set of documents including "C.S0002-A Physical Layer Standard for cdma2000 Spread Spectrum Systems," the "
• UE wireless user equipment
• cellular radio networks such as cellular telephones.
• UEs include display screens with sufficient resolution to render video presentations.
• Multimedia Broadcast Multicast Service is a broadcasting service that can be offered via existing Global System for Mobile Communications (GSM) and Universal Mobile Telecommunications System (UMTS) cellular networks.
• GSM Global System for Mobile Communications
• UMTS Universal Mobile Telecommunications System
• E-MBMS enhanced version
• 3GPP Third Generation Partnership Project
• Downlink (DL) capacity is an important performance characteristic of cellular systems. Increased downlink capacity can be used, for example, to make more broadcast/multicast channels available to the subscribers, and to improve the quality of the broadcast transmissions. For a fixed frequency range available for cellular system transmissions, capacity depends on spectral efficiency. Given limited availability of electromagnetic spectrum, it is therefore desirable to increase spectral efficiency of cellular systems, including spectral efficiency of broadcasts and multicasts. To avoid costs associated with infrastructure updating, it is desirable to increase spectral efficiency of existing infrastructure without or with limited changes. [0009] Many base transceiver stations (BTSs) of existing cellular radio network sites (BTSs) of existing cellular radio network sites).
• BTSs base transceiver stations
• Nodes-B have a single transmit antenna for single frequency network (SFN) operation. There is therefore a need in the art for methods and apparatus that increase SFN broadcast and multicast spectral efficiency of cellular networks without requiring installation of multiple antennae at existing cellular sites.
• SFN single frequency network
• Embodiments disclosed herein address the above stated needs by providing a method for transmitting data from a plurality of sectors in a cellular communication system.
• the method includes assigning at least one transmit antenna from each sector of the plurality of sectors to a transmit antenna set of a plurality of L (L being an integer greater than 1) transmit antenna sets.
• Each transmit antenna set includes at least one transmit antenna of the cellular communication system.
• the method also includes arranging the data into a plurality of L data streams (e.g., partitioning into the streams, or keeping the streams separate). During at least one first period, each data stream is assigned to a different transmit antenna set of the L transmit antenna sets, resulting in a first distribution of data streams among transmit antenna sets.
• the method also includes, for each transmit antenna set of the plurality of L transmit antenna sets, modulating during the at least one first period a carrier of a first frequency with the data stream assigned to the transmit antenna set during the at least one first period.
• the method further includes transmitting to a plurality of receivers during the at least one first period the carrier through the transmit antennae of the plurality of L transmit antenna sets so that transmit antennae of each transmit antenna set transmit during the at least one first period the data stream assigned to each transmit antenna set for the at least one first period.
• a cellular communication system includes a radio network controller and a plurality of sectors. Each sector has at least one transmit antenna and at least one base transceiver station.
• the radio network controller is configured to perform the following operations:
• machine-readable medium stores instructions for a processor of a radio network controller for a cellular communication system that has a plurality of sectors with transmit antennae.
• the instructions configure the radio network controller to perform these operations:
• a method for transmitting data from a plurality of sectors in a cellular communication system. The method includes the following steps: ' [0024] 1. Assigning at least one transmit antenna of each sector into a first transmit antenna set or a second transmit antenna set, each antenna set of the first and second transmit antenna sets having at least one transmit antenna;
• [0026] Hierarchically modulating a carrier of a given frequency to obtain a first signal having a first base layer and a first enhancement layer; [0027] 4. Hierarchically modulating the carrier to obtain a second signal having a second base layer and a second enhancement layer; [0028] 5. Transmitting the first signal through each transmit antenna in the first transmit antenna set; and [0029] 6. Transmitting the second signal through each antenna in the second transmit antenna set. [0030] In this method, the steps of hierarchically modulating are performed so that the first base layer carries information of the first data stream, the first enhancement layer carries information of the second data stream, the second base layer carries information of the second data stream, and the second enhancement layer carries information of the first data stream.
• a cellular communication system has a radio network controller and a plurality of sectors. Each sector has at least one transmit antenna.
• the radio network controller is configured to perform the following operations: [0032] 1. Assigning the at least one transmit antenna of each sector of the plurality of sectors into a first transmit antenna set or a second transmit antenna set, each antenna set of the first and second transmit antenna sets including at least one transmit antenna; [0033] 2. Arranging data into a first data stream and a second data stream;
• [0034] Causing hierarchical modulation of a carrier of a given frequency to obtain a first signal having a first base layer and a first enhancement layer (for example, sending commands to perform such modulation to appropriate sectors); [0035] 4. Causing hierarchical modulation of the carrier to obtain a second signal having a second base layer and a second enhancement layer (for example, sending commands to perform such modulation to appropriate sectors); [0036] 5. Causing transmission of the first signal through each transmit antenna in the first transmit antenna set (for example, sending commands to perform such transmission to appropriate sectors); and [0037] 6.
• machine-readable medium stores instructions for at least one processor of a radio network controller for a cellular communication system.
• the cellular communication system includes a plurality of sectors, each sector having at least one transmit antenna.
• the instructions configure the radio network controller to perform the following operations: [0040] 1. Assigning at least one transmit antenna of each sector into a first transmit antenna set or a second transmit antenna set, each transmit antenna set including at least one transmit antenna;
• the first base layer carries information of the first data stream
• the first enhancement layer carries information of the second data stream
• the second base layer carries information of the second data stream
• the second enhancement layer carries information of the first data stream.
• a method for transmitting data from a plurality of sectors in a cellular communication system in which each of the sectors has at least one transmit antenna.
• the method includes these steps: [0048] 1. Arranging the data into a plurality of data streams;
• a cellular radio network has a radio network controller and a plurality of cells. Each cell has at least one transmit antenna.
• the radio network controller is configured to perform the following operations: [0053] 1. Arranging data into a plurality of data streams;
• a machine-readable medium stores instructions for at least one processor of a radio network controller of a cellular radio network.
• the cellular radio network has a plurality of cells, each cell with at least one transmit antenna.
• the instructions configure the radio network controller to perform the following operations: [0058] 1. Arranging data into a plurality of data streams;
• a method for receiving data sent from a cellular communication system.
• the method includes receiving at a first antenna a first signal during one or more first time periods.
• the first signal is carried on a first frequency and contains a first data stream transmitted through a first physical channel, and a second data stream transmitted through a second physical channel.
• the first data stream has first data during the one or more first time periods, and the second data stream has second data during the one or more first time periods.
• the method also includes receiving at a second antenna a second signal during the one or more first time periods.
• the second signal is also carried on the first frequency.
• the second signal contains the first data stream transmitted through a third physical channel, and the second data stream transmitted through a fourth physical channel.
• the method also includes estimating the first, second, third, and fourth physical channels to obtain first, second, third, and fourth channel estimates.
• the method also includes separating the first and second data streams from at least one of the first signal and the second signal using the channel estimates.
• the receiver is configured to receive at the first antenna a first signal during one or more first time periods.
• the first signal is carried on a first frequency, and contains a first data stream transmitted through a first physical channel and a second data stream transmitted through a second physical channel.
• the first data stream carries first data during the one or more first time periods
• the second data stream carries second data during the one or more first time periods.
• the receiver is also configured to receive at the second antenna a second signal during the one or more first time periods.
• the second signal is also being carried on the first frequency.
• the second signal contains the first data stream transmitted through a third physical channel, and the second data stream transmitted through a fourth physical channel.
• the processor is configured to estimate the first, second, third, and fourth physical channels to obtain channel estimates, and to separate the first and second data streams from at least one of the first signal and the second signal using the channel estimates.
• a machine-readable medium stores instructions for a processor of a wireless user equipment device for communicating with a cellular communication system.
• the instructions When executed by the processor, they cause the wireless user equipment device to receive from the cellular communication system at a first antenna a first signal during one or more first time periods.
• the first signal is carried on a first frequency and contains a first data stream transmitted through a first physical channel, and a second data stream transmitted through a second physical channel.
• the first data stream carries first data during the one or more first time periods
• the second data stream carries second data during the one or more first time periods.
• the instructions further cause the wireless user equipment device to receive from the cellular communication system at a second antenna a second signal during the one or more first time periods.
• the second signal is also carried on the first frequency.
• the second signal contains the first data stream transmitted through a third physical channel, and the second data stream transmitted through a fourth physical channel.
• the instructions further cause the wireless user equipment device to estimate the first, second, third, and fourth physical channels to obtain channel estimates, and separate the first and second data streams from at least one of the first signal and the second signal using the channel estimates.
• a method for receiving data sent from a cellular communication system.
• the method includes receiving at a first antenna a first signal.
• the first signal contains a first signal component transmitted through a first physical channel, and a second signal component transmitted through a second physical channel.
• the first signal component has a first base layer carrying a first data stream and a first enhancement layer carrying a second data stream.
• the second signal component contains a second base layer carrying the second data stream, and a second enhancement layer carrying the first data stream.
• the method also includes receiving at a second antenna a second signal.
• the second signal contains a third signal component transmitted through a third physical channel and a fourth signal component transmitted through a fourth physical channel.
• the third signal component has a third base layer carrying the first data stream, and a third enhancement layer carrying the second data stream.
• the fourth signal component has a fourth base layer carrying the second data stream, and a fourth enhancement layer carrying the first data stream.
• the method also includes estimating the first, second, third, and fourth physical channels to obtain one or more channel estimates, and separating the first and second signal components using the channel estimates. After separating, the first data stream is decoded from the first base layer, and the second data stream is decoded from at least one of the first enhancement layer and the second base layer. Note that the first, second, third, and fourth signal components are hierarchically modulated using the same carrier frequency.
• the receiver is configured to receive at the first antenna a first signal, and to receive at the second antenna a second signal.
• the first signal contains a first signal component transmitted through a first physical channel, and a second signal component transmitted through a second physical channel.
• the first signal component has a first base layer carrying a first data stream, and a first enhancement layer carrying a second data stream.
• the second signal component has a second base layer carrying the second data stream, and a second enhancement layer carrying the first data stream.
• the second signal contains a third signal component transmitted through a third physical channel, and a fourth signal component transmitted through a fourth physical channel.
• the third signal component has a third base layer carrying the first data stream, and a third enhancement layer carrying the second data stream.
• the fourth signal component has a fourth base layer carrying the second data stream, and a fourth enhancement layer carrying the first data stream.
• the first, second, third, and fourth signal components are hierarchically modulated using the same carrier frequency.
• the processor is configured to estimate the first, second, third, and fourth physical channels to obtain channel estimates, and to separate the first and second signal components using the channel estimates.
• the processor is further configured to decode, after separating, the first data stream from the first base layer, and the second data stream from the first enhancement layer and/or the second base layer.
• a machine-readable medium stores instructions for a processor of a wireless user equipment device. When executed by the processor, the instructions cause the wireless user equipment device to receive at a first antenna a first signal, and receive at a second antenna a second signal.
• the first signal contains a first signal component transmitted through a first physical channel, and a second signal component transmitted through a second physical channel.
• the first signal component has a first base layer carrying a first data stream, and a first enhancement layer carrying a second data stream.
• the second signal component has a second base layer carrying the second data stream, and a second enhancement layer carrying the first data stream.
• the second signal contains a third signal component transmitted through a third physical channel, and a fourth signal component transmitted through a fourth physical channel.
• the third signal component has a third base layer carrying the first data stream, and a third enhancement layer carrying the second data stream.
• the fourth signal component has a fourth base layer carrying the second data stream, and a fourth enhancement layer carrying the first data stream.
• the first, second, third, and fourth signal components are hierarchically modulated using the same carrier frequency.
• the instructions further cause the wireless user equipment device to estimate the first, second, third, and fourth physical channels to obtain channel estimates, and to separate the first and second signal components using the channel estimates. After separating, the instructions cause the wireless user equipment device to decode the first data stream from the first base layer, and to decode the second data stream from the first enhancement layer and/or the second base layer.
• a method for operating a cellular radio network with first and second spatially diverse transmit antennae in a first cell.
• the antennae are spatially diverse to enable MEMO.
• the method includes transmitting (e.g., broadcasting, multicasting) a first data stream on a first frequency through the first antenna to a plurality of user equipment devices in communication with the network.
• the method also includes transmitting a second data stream on the first frequency through the second antenna to the plurality of user equipment devices.
• At least some of the user equipment devices have multiple spatially diverse receive antennae. In this way, the use of multiple transmit and multiple receive antennae enables increased spectral efficiency of the transmissions.
• Figure 1 is a high-level block diagram showing a cellular radio network transmitting to user equipment devices using Multiple-In Multiple-Out (MIMO) technique, in accordance with an embodiment of the present invention
• Figure 2 is a high-level block diagram showing selected components of a radio network controller of the network of Figure 1, in accordance with an embodiment of the present invention
• Figure 3 is a high-level block diagram showing selected components of user equipment devices of Figure 1, in accordance with an embodiment of the present invention
• Figure 4 is a high-level block diagram showing another cellular radio network transmitting to user equipment devices using MIMO and time division multiplexing/permuting, in accordance with an embodiment of the present invention
• Figure 5 is a diagram illustrating time division multiplexing/permuting in the network of figure 4, in accordance with an embodiment of the present invention
• Figure 6 is a high-level block diagram showing another cellular radio network transmitting to user equipment devices using MEVIO and hierarchical modulation, in accordance with an embodiment of the present invention
• the words “embodiment,” “variant,” and similar expressions are used to refer to particular apparatus, process, or article of manufacture, and not necessarily to the same apparatus, process, or article of manufacture.
• “one embodiment” (or a similar expression) used in one place or context can refer to a particular apparatus, process, or article of manufacture; the same or a similar expression in a different place can refer to a different apparatus, process, or article of manufacture.
• the expression “alternative embodiment” and similar phrases are used to indicate one of a number of different possible embodiments. The number of possible embodiments is not necessarily limited to two or any other quantity.
• a "set" means one item or a plurality of items.
• a transmit antenna set may include one transmit antenna or a plurality of transmit antennae.
• Base transceiver stations (BTSs) and base station controllers (BSCs) are parts of a network called "radio network,” “RN,” “access network,” or “AN.”
• a base station controller may also be referred to as a radio network controller or "RNC.”
• a radio network may be a UTRAN or UMTS Terrestrial Radio Access Network.
• the radio network may transport data packets between multiple user equipment devices.
• the radio network may be further connected to additional networks outside the radio network, such as a corporate intranet, the Internet, or a conventional public switched telephone network (“PSTN”), and may transport data packets between each user equipment device and such outside networks.
• PSTN public switched telephone network
• Single frequency network or “SFN” is a radio network that operates several transmitters on the same frequency. To avoid or reduce interference, the several transmitters may be synchronized. Thus, the same signal is sent from the several transmitters.
• a single frequency network may also be configured to transmit multiple streams/flows of data on the same frequency, each data stream or flow being transmitted from a different set of transmitters of the network.
• MEVIO multiple-input multiple-output
• MEVIO uses multiple spatially-diverse transmit antennae at a transmitting entity, and multiple spatially-diverse antennae at a receiver.
• N ⁇ ,i and N ⁇ , 2 and two receive antennae N R)1 and N Rj2 four physical transmission channels are present: CH 1;1 between N T , i and N R11 , CH 1>2 between N T, i and N R)2 , CH 2J1 between N ⁇ >2 and N R;1 , and CH 2 , 2 between N ⁇ , 2 and N R>2 .
• the notation CHi j corresponds to a channel between a transmit antenna NT 1 ,- and a receive antenna N R J.
• Each of these channels is subjected to channel conditions, such as delay, interference, noise, multipath/fading, dispersion, and distortion. Because of the spatial diversity of the receive and transmit antennae, the combined effects of these conditions are typically different for each of these channels.
• h a channel coefficient corresponding to a channel CH J0 -
• j a channel matrix H representing all the channels between N T transmit antennae and N R receive antennae
• each coefficient hy need not be a simple multiplier coefficient, but encompasses all factors affecting the associated channel.
• a first transmit stream TSi (on a given frequency F) being transmitted from N ⁇ ,i
• a second stream TS 2 being transmitted from N ⁇ , 2
• a first receive stream RSj is received at N R;1
• a second receive stream RS 2 is received at N RJ2 .
• the two receive streams may be represented as follows:
• RS2 TSi*hi,2 + TS2*h2,2.
• each transmit stream is broadcast from a single antenna. It is also possible to broadcast one stream from multiple transmit antennae. In this latter case, we can treat each channel coefficient hy as a coefficient of the transmission channel from the zth set of antennae that transmit a stream TSi to a receive antenna (or a set of receive antennae) j.
• the analytical treatment of this latter case is similar to the analytical treatment of the case of one transmit stream per transmit antenna.
• Open loop MEMO techniques can be used as an additional option for increasing spectral efficiency of cellular SFN broadcasting and multicasting. Because MEMO uses multiple transmit antennae, one way to employ MEVlO is to transmit multiple streams from multiple antennae of the same site or sector ("cell").
• the receive signal-to-noise ratio (SNR) at a UE can be very high; for the macro-cell link budget with 2800 meter inter-site distance, the SNR is typically higher than 14 dB for 95% of the users.
• SNR receive signal-to-noise ratio
• Some system simulations show that, in a 1x1 deployment, for 95% coverage, the SFN spectral efficiency of E-MBMS is 1.2 bps/Hz. Given the presence of multiple transmit and receive antennae, such a high SNR makes it feasible to use open loop (without feedback) MEVIO as an additional option for E-MBMS.
• S Number of transmit (Tx) streams
• N Number of cells (sectors).
• N T Number of transmit antennae per cell
• N R Number of receive (Rx) antennae per cell.
• Figure 1 shows a cellular single frequency radio network 105 that includes a radio network controller 110, and cells 120 and 130. Each of these cells has a base transmitter station and two Tx antennae: the cell 120 has a BTS 121 and transmit antennae 122A and 122B, while the cell 130 has a BTS 131 and transmit antennae 132A and 132B. A UE 140 has two Rx antennae, 142A and 142B.
• a specific open loop MTMO variant of this embodiment uses a generic cyclic or pseudo random antenna permutation (PRAP) scheme, wherein S streams with identical Modulation and Code Set (MCS) combinations are transmitted from each cell. Note that this makes the scheme similar to a variation of Horizontal Bell Labs Layered Space Time Code (H-BLAST).
• PRAP generic cyclic or pseudo random antenna permutation
• MCS Modulation and Code Set
• H-BLAST Horizontal Bell Labs Layered Space Time Code
• FIG. 2 illustrates selected components of an exemplary embodiment of the radio network controller 110.
• the radio network controller 110 includes a BTS interface 111 to enable the RNC 110 to communicate with the BTSs 120 and 130, a processor 112, and a memory device 113 storing computer code instructions.
• the processor 112 is coupled to the memory device 113 and to the BTS interface 111, so that the processor 112 reads and executes the code stored in the memory device 113, configuring the BTS interface 111 to cause the BTSs 120 and 130 to communicate with the UE 140 and other UEs using the processes described throughout this document.
• the radio network may include additional controllers.
• Figure 3 illustrates selected components of an exemplary embodiment of the UE
• the UE 140 includes receive antennae 142A and 142B, a radio network transceiver (receiver and transmitter) 143, an encoder/decoder block 144, a user input device (e.g., a keypad) 145, a display (e.g., an LCD screen) 146, a processor 147, and a memory device 148.
• the radio network transceiver 143, encoder and decoder block 144, user input device 145, and display 146 are configured by the processor 147 under control of the code stored in the memory device 148.
• the user equipment device 140 is configured to communicate with the radio network 105 over wireless communication links using a wireless cellular network transmission protocol, such as the cellular packet transmission protocols described above, and to execute processes described throughout this document.
• Additional UEs may be in communication with the radio network 105.
• the radio network may also include additional base transceiver stations.
• the radio network 105 may transmit to the UE 140 using Orthogonal Frequency
• each stream may be transmitted from the radio network 105 to the UE 140 on a separate antenna; further, the mapping of stream DD to transmit antenna ID is permuted in time, so that the Rx SNR for each stream is approximately identical.
• the pilot sub-carriers are not re-used across Tx antennae. This is unlike data sub-carrier indices, which are re-used across all Tx antennae. Therefore, the following holds:
• H 11 [R] Channel frequency response on sub -carrier k from cell i and antenna j,
• the composite SFN channel frequency response for each Tx antenna can be estimated using, for example, a Minimum Mean Square Error (MMSE) or low complexity zero-forced Robust MMSE solution.
• MMSE Minimum Mean Square Error
• stream separation and inter-stream interference suppression may be achieved using a MMSE filter. This can be written by invoking the MMSE filter.
• each stream may be independently decoded, and then successively canceled out from all other streams. Cancellation steps may be iterated until all streams are decoded.
• the complexity of successive interference cancellation (SIC) depends on the number of streams.
• the receiver receives a first signal using a first receive antenna, and a second signal using a second receive antenna.
• the first signal includes a first data stream transmitted through a first physical channel from a first transmit antenna or a first set of transmitter antennae, and a second data stream transmitted through a second physical channel from a second transmit antenna or a second set of transmit antennae.
• the second signal includes the first data stream transmitted through a third physical channel, and the second data stream transmitted through a fourth physical channel.
• the four channels are estimated, for example, using pilot channels at the receiver, or at the radio network with data provided by the receiver.
• the first and second data streams can then be separated by the receiver to obtain a first separated data stream and a second separated data stream. After separation, the receiver attempts to decode first data in the first data stream and second data in the second data stream. If the first attempt to decode the data is not successful, the receiver may attempt to decode again after cancelling the interference based on the partial decoding obtained during the first attempt.
• the first and the second data streams may be multicast or broadcast on common channel(s).
• NT I (i.e. , one transmit antenna per cell).
• the SNR may be lower than in the strict SNF operation where all cells transmit the same stream, because each stream may be transmitted from a partial subset of the network's cells. Nevertheless, it is likely that the SNR is still high enough to exploit spatial multiplexing gains. This is particularly so if the number of such sets/streams is small and, consequently, the number of transmit antennae in each set is relatively large, providing good coverage throughout the geographic area of interest.
• FIG. 4 illustrates a single frequency radio network 405 using TDM and MIMO to broadcast or multicast to UEs 440A and 440B.
• the radio network 405 includes a radio network controller 410 and cells/BTSs 420, 424, 428, and 432. (Each cell is conterminous with a BTS in this embodiment, but this need not always be the case.)
• the BTSs have respective transmit antennae 421, 425, 429, and 433.
• the structure of the radio network controller 410 may be similar or identical to the structure of the radio network controller 110.
• the structure of each of the UEs 440A/B may also be the same as or similar to the structure of the UE 140.
• the radio network 405 and the UEs 440A/B are configured to communicate in accordance with the methods described below in relation to this embodiment.
• S NR , a generic PRAP or Code Re-use BLAST (CR-
• N BLAST N BLAST
• N R streams are transmitted from cells at any given time.
• Each of the N R streams thus corresponds to a set of transmit antennae in the associated set of cells.
• the mapping of streams to transmit antenna sets is permuted in time.
• multiple streams are multiplexed in a time division multiplexed manner on a single transmit antenna per cell.
• half the symbols per slot may be dedicated to one stream, and the other half of the symbols are dedicated to the second stream.
• Tl a first period of time
• a first stream of symbols is transmitted from a first set of transmit antennae that includes the transmit antennae 425 and 433 of the BTSs 424 and 432
• a second stream of symbols is transmitted from a second set of transmit antennae that includes transmit antennae 421 and 429 of the BTSs 420 and 428.
• the first stream is transmitted from the second transmit set, while the second stream is transmitted from the first transmit set.
• the cycle is then repeated with the stream-antenna set mapping being switched again and again.
• FIG 5 shows time periods Tl-I through Tl-N during which the radio network transmits the first stream from the first set, and the second stream from the second set; similarly, the radio network transmits the first stream from the second set and the second stream from the first set during time periods T2-1 through T2-N.
• the UEs in cell interiors, such as the UE 440B benefit from temporal multiplexing and high CIl.
• the UE 440B may receive only one of the streams at a time, but with a relatively high C/I ratio and concomitantly high SNR, particularly in view of the proximity of the UE 440B to a transmit antenna.
• each stream may be independently decoded, and then successively canceled out from all other streams. Cancellation steps may be iterated until all streams are decoded.
• the complexity of successive interference cancellation (SIC) depends on the number of streams.
• the receiver of this embodiment may receive, during one or more first time periods, a first signal using a first receive antenna, and a second signal using a second receive antenna.
• the first signal includes. (1) a first data stream transmitted through a first physical channel from a first transmit antenna or a first set of transmit antennae, and (2) a second data stream transmitted through a second physical channel from a second transmit antenna or a second set of transmit antennae.
• the second signal includes the first data stream transmitted through a third physical channel, and the second data stream transmitted through a fourth physical channel.
• the first data stream carries first data during the first time period(s), and the second data stream carries second data during the first time period(s).
• the four channels are estimated, for example, using pilot channels at the receiver.
• the first and second data streams can then be separated by the receiver to obtain a first separated data stream and a second separated data stream. After separation, the receiver attempts to decode the first data in the first data stream and the second data in the second data stream.
• the receiver may attempt to decode again after cancelling the interference based on the partial decoding obtained during the first attempt.
• the receiver may also attempt to decode the data from the signals received during subsequent time period or periods. Thus, if the first attempt to decode is not successful, the receiver may receive at the first antenna the first signal during one or more second time periods, and receive at the second antenna the second signal during the one or more second time periods. The receiver may separate the first and second data streams from at least one of the first signal and the second signal using some or all of the channel estimates, to obtain first separated data stream and second separated data stream of the second time periods. After the streams are separated, the receiver may again attempt to decode the first and the second data from the first and second separated data streams of the first and second time periods.
• the first signal during the second periods includes the second data stream transmitted through the first physical channel and the first data stream transmitted through the second physical channel
• the second signal includes the second data stream transmitted through the third physical channel and the first data stream transmitted through the fourth physical channel.
• the first data stream carries the first data during the second time periods
• the second data stream carries the second data during the second time periods.
• the data may be transmitted redundantly during the first and second time period(s).
• the first and the second data streams may be multicast or broadcast on common channel(s).
• Figure 6 illustrates a single frequency radio network 605 using Hierarchical
• the radio network 605 which is similar to the network 405 of Figure 4, includes a radio network controller 610 and cells/BTSs 620, 624, 628, and 632. The cells have respective transmit antennae 621, 625, 629, and 633.
• the structure of the radio network controller 610 may be similar or identical to the structure of the radio network controller 110, which is shown in Figure 2.
• the structure of each of the UEs 640A/B may also be the same as or similar to the structure of the UE 140, which is shown in Figure 3.
• the radio network and the UEs 640A/B are configured to communicate in accordance with the methods described below in relation to this embodiment.
• S NR
• N R streams are transmitted from cells at any given time.
• the streams are carried by hierarchically modulated signals.
• QPSK Quadrature Amplitude Modulation
• symbols are encoded onto a carrier so that different sections in the complex signal plane of the modulation constellation (such as the Q-I plane) represent different positions of the symbol alphabet bits.
• the left part of the Q-I plane may correspond to the "1" value of the most significant bit of a symbol, and the right half of the plane may correspond to the "0" value of this bit.
• the lower half of the plane may correspond to the "1" value of the second most significant bit position
• the top half of the plane may correspond to the "0" value of this bit.
• a symbol falling in the top left quadrant would represent “10” in the two most significant bit positions
• a symbol in the top right quadrant would represent “00” in these positions
• symbols in the bottom left and bottom right quadrants would represent "11" and "01” values, respectively.
• Additional bits of the symbol corresponding to the 16-QAM data flow are determined by the symbol's position within the particular quadrant determined by the first two bits.
• the QPSK data flow is more robust than the 16-QAM data flow, meaning that the QPSK data flow may be decoded at lower SNR and lower C/I ratios of the signal. Spacing within the constellation may be varied to provide additional robustness to the QPSK data flow at the cost of the 16-QAM data flow. Thus, the more- robust BPSK data flow has a greater coverage than the less-robust 16-QAM data flow. [00144] In this document, the more robust layer of a hierarchically modulated signal
• the base layer (such as the BPSK stream in the 64-QAM example above)
• the less robust layer of the hierarchically modulated signal (such as the 16-QAM stream of the 64-QAM example) will be referred to as the enhancement layer.
• Hierarchical modulation provides a mechanism for increasing transmission capacity.
• the capacity increase comes at the expense of reduced coverage for enhancement layer, while the base layer performance is improved.
• the stream mapping may be permuted in time from base to enhancement layers.
• a first data stream Sl may be transmitted from the first set of antennae on the base layer of a first hierarchically modulated signal and, concurrently, from the second set of antennae on the enhancement layer of a second hierarchically modulated signal.
• the first data stream may be transmitted from the first set of antennae on the enhancement layer of the first hierarchically modulated signal and, concurrently, from the second set of antennae on the base layer of the second hierarchically modulated signal.
• the second layer is transmitted on the enhancement layer of the same set, and vice versa.
• data in each stream may be redundantly transmitted during successive time periods.
• a receiver may be configured to receive at a first receive antenna a first receive signal that includes (1) the first signal component transmitted from a first transmit antenna (or a first set of transmit antennae) through a first physical channel, and (2) a second signal component transmitted from a second transmit antenna (or a second set of transmit antennae) through a second physical channel.
• the first signal component may include (1) a first base layer carrying a first data stream, and (2) a first enhancement layer carrying a second data stream; the second signal component may include (1) a second base layer carrying the second data stream, and (2) a second enhancement layer carrying the first data stream.
• the receiver may be further configured to receive at a second antenna a second signal that includes (1) a third signal component transmitted through a third physical channel, and (2) a fourth signal component transmitted through a fourth physical channel.
• the third signal component may include (1) a third base layer carrying the first data stream, and (2) a third enhancement layer carrying the second data stream;
• the fourth signal component may include (1) a fourth base layer carrying the second data stream, and (2) a fourth enhancement layer carrying the first data stream.
• the first, second, third, and fourth physical channels may be estimated to obtain channel estimates for the channels.
• Channel estimation may be performed by the receiver and be based on pilot channels. After some or all the channel estimates become available, the receiver may separate the first and second signal components. After the signal separation, the receiver may attempt to decode the first data stream from the first base layer and the second data stream from the first enhancement layer.
• the receiver may attempt to decode the second data stream from both the first enhancement layer and the second base layer.
• the receiver may estimate the quality of the first signal and, if the quality of the first signal (e.g., SNR) is higher than a predetermined measure, decode the second data stream from the first enhancement layer; if the quality of the first signal does not exceed the measure, the receiver may separate the third and fourth signal components using the channel estimates, and attempt decode the second data stream from the second base layer.
• the quality of the first signal e.g., SNR
• the receiver may also estimate the quality of the second signal and, if the quality of the second signal is below a predetermined threshold, attempt to decode the second data stream from the first enhancement layer; if the quality of the second signal is not below the threshold, the receiver may separate the third and fourth signal components and attempt to decode the second data stream from the second base layer.
• Interference Cancellation (IC) techniques may be used to cancel the interference from base layer to enhancement layer of the same signal.
• the system can switch to Space Time Transmit Diversity (STTD), or turn off the transmit diversity antennae.
• STTD Space Time Transmit Diversity
• the first of these options may be simpler with no RF implications of dynamic switching on/off the transmit diversity antennae.
• steps of the various methods have been described serially in this disclosure, some of these steps may be performed by separate elements in conjunction or in parallel, asynchronously or synchronously, in a pipelined manner, or otherwise. There is no particular requirement that the steps be performed in the same order in which this description lists them, except where explicitly so indicated, otherwise made clear from the context, or inherently required. Furthermore, not every illustrated step or communication message is necessarily required in every embodiment in accordance with the invention, while some steps or communication messages that have not been specifically illustrated may be desirable in some embodiments in accordance with the invention.
• DSP digital signal processor
• ASIC application specific integrated circuit
• FPGA field programmable gate array
• a general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine.
• a processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
• a software module may reside in random access memory (RAM), flash memory, read only memory (ROM), erasable programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), registers, hard disk, removable disk, CD- ROM, or any other form of storage medium known in the art.
• An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium.
• the storage medium may be integral to the processor.
• the processor and the storage medium may reside in an ASIC.
• the ASIC may reside in a user equipment device.
• the processor and the storage medium may reside as discrete components in a user equipment device.

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