CN101238648B - Method and apparatus for broadcasting and multicasting from a cellular radio network - Google Patents

Abstract

Multiple Input Multiple Output (MIMO) techniques are used to improve the spectral efficiency of cellular single frequency networks. In some embodiments with a single transmit antenna per cell, multiple data streams are transmitted from multiple cells, one data stream for each transmit antenna group. The mapping of the streams to the antenna groups is set in time. In this way, user equipment devices (UEs) at the cell edge benefit from MIMO, and UEs near the cell center benefit from a high carrier-to-interference (C/I) ratio of the signal. In some embodiments, each stream is transmitted simultaneously on a base layer of a hierarchical modulated signal from one group and on an enhancement layer of a hierarchical modulated signal from another group. The mapping of groups to streams is permuted in time. UEs at the cell edge benefit from MIMO, while UEs near the cell center benefit from a high C/I to decode both streams from the base and enhancement layers.

Description

Method and apparatus for broadcasting and multicasting from a cellular radio network

Claim of priority under 35 U.S.C §119

This patent application claims priority over provisional application Serial No. 60/690,622, filed June 14, 2005, entitled "Transmit Diversity For E-MBMS." Said provisional application is assigned to the assignee of the present application and is expressly incorporated herein by application as if fully set forth herein, including all figures and tables. the

technical field

The present invention relates generally to telecommunications, and more particularly to methods, apparatus and articles of manufacture for broadcast and multicast from cellular radio networks. the

Background technique

Modern communication systems are expected to provide reliable data transmission for a variety of applications, including voice and data applications. In the context of point-to-multipoint communication, known communication systems are based on frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA) and possibly other multiple access communication schemes . the

A CDMA system may be designed to support one or more CDMA standards: For example, (1) "TIA/EIA-95 Mobile Stations - Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular Mobile Systems" (the standard and its enhanced revision may be referred to as the "IS-95 Standard"); (2) "TIA/EIA-98-C Recommended Minimum Standard for Dual-Mode Wideband Spread Spectrum Cellular Mobile Stations" (which may also be referred to as the "IS- 98 standard"); (3) standards sponsored by a consortium called the "Third Generation Partnership Project" (3GPP), which are included in a group of and 3G TS 25.214 (“W-CDMA Standard”); (4) a standard sponsored by a consortium named “3rd Generation Partnership Project 2 (3GPP2)” contained in a set of C.S0002-APhysical Layer Standard for cdma2000 Spread Spectrum Systems", "C.S0005-A UpperLayer (Layer 3) Signaling Standard for cdma2000 Spread Spectrum Systems" (collectively referred to as "cdma 2000 standard"); (5) 1 x EV-DO standard "TIA/EIA/IS-856 cdma2000 High-Speed Packet Data Air Interface Specification"; and (6) certain other standards. The above-enumerated standards are incorporated herein by reference as if fully set forth herein, including appendices, appendices, and other appurtenances. the

Manufacturers continue to add performance enhancing features to wireless user equipment (UE) devices for use with cellular radio networks, eg, cellular telephones. For example, many UEs include display screens with sufficient resolution to represent video images. the

With the enhanced capabilities of their UEs, users are becoming more interested in being able to receive television broadcasts. As long as there is demand, there will be supply. It is worth noting that there is already a cellular infrastructure for transmitting to UEs. Accordingly, operators of cellular networks will benefit from providing broadcast or multicast services to their subscribers. Live television, movies, motion clips, talk shows can all be broadcast or multicast from cellular radio networks, in addition to the more conventional services provided by these networks. In practice, this may be similar to providing cable or satellite channels directly to UEs. the

Multimedia Broadcast Multicast Service (MBMS) is a broadcast service available over existing Global System for Mobile Communications (GSM) and Universal Mobile Telecommunications System (UMTS) cellular networks. MBMS and its enhanced version (E-MBMS) are being standardized in various 3GPP (Third Generation Partnership Project) groups. the

Downlink (DL) capacity is an important performance characteristic of cellular systems. The increased downlink capacity can be used, for example, to provide more broadcast/multicast channels to subscribers and to improve the quality of broadcast transmissions. For the fixed frequency range available for cellular system transmission, capacity depends on spectral efficiency. Given the limited availability of the electromagnetic spectrum, it is therefore desirable to increase the spectral efficiency of cellular systems, including broadcast and multicast. To avoid the costs associated with infrastructure updates, it is desirable to increase the spectral efficiency of existing infrastructure with limited or no changes. the

Many Base Transceiver Stations (BTS) of existing cellular radio sites (Node-Bs) have a single transmit antenna for Single Frequency Network (SFN) operation. Therefore, there is a need in the art for methods and apparatus that increase the SFN broadcast and multicast spectral efficiency of cellular networks without requiring the installation of multiple antennas at existing cellular sites. the

Contents of the invention

Embodiments disclosed herein address the aforementioned needs by providing a method for transmitting data from multiple sectors in a cellular communication system. The method includes assigning at least one transmit antenna from each of a plurality of sectors to one of a plurality L of transmit antenna groups, where L is an integer greater than one. Each transmit antenna group 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 (eg, splitting into several streams, or keeping the streams separate). During at least one first period, each data stream is assigned to a different one of the L transmit antenna groups, resulting in a first assignment of the data stream among the transmit antenna groups. The method also includes: for each transmit antenna group of the plurality of L transmit antenna groups, during the at least one first period using the The data stream modulates a carrier of the first frequency. The method further comprises: during the at least one first period, transmitting the carrier wave to a plurality of receivers via transmit antennas of a plurality of L transmit antenna groups such that the transmit antennas of each transmit antenna group are at the The data streams assigned to the each transmit antenna group for the at least one first period are transmitted during the at least one first period. the

In one embodiment, 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:

1. Assign at least one transmit antenna from each of a plurality of sectors to one of a plurality of L transmit antenna groups (where L is an integer greater than 1), such that the plurality Each of the L transmit antenna groups has at least one transmit antenna of the cellular communication system;

2. Arrange the data into multiple L data streams;

3. For at least one first period, assigning each data stream to a different one of the L transmit antenna groups;

4. For each transmit antenna group in the plurality of L transmit antenna groups, causing the plurality of sectors to be assigned to the the data stream for each transmit antenna group modulates a carrier at the first frequency; and

5. Causing the plurality of sectors to transmit the carrier to a plurality of receivers via the transmit antennas of the plurality of L transmit antenna groups during the at least one first period such that each transmit antenna The transmit antennas of the group transmit during the at least one first period the data streams assigned to the each transmit antenna group for the at least one first period. the

In one embodiment, a machine-readable medium may store instructions for a processor of a radio network controller of a cellular communication system having multiple sectors with transmit antennas. When executed by the processor, the instructions configure the radio network controller to:

1. Assigning at least one transmit antenna from each sector in the plurality of sectors to one of a plurality of L transmit antenna groups (where L is an integer greater than 1), each transmit antenna set has at least one transmit antenna of a cellular communication system;

2. Arrange the data into multiple L data streams;

3. For at least one first period, assigning each data stream to a different one of the L transmit antenna groups;

4. For each of the plurality of L transmit antenna groups, causing the plurality of sectors for the at least one first period to be assigned to each of the at least one first period during the at least one first period A data stream of a transmitting antenna group modulates a carrier wave of a first frequency;

5. Causing the plurality of sectors to transmit the carrier to a plurality of receivers via the transmit antennas of the plurality of L transmit antenna groups during the at least one first period such that each transmit antenna The transmit antennas of the group transmit during the at least one first period the data streams assigned to the each transmit antenna group for the at least one first period. the

In one embodiment, a method for transmitting data from multiple sectors in a cellular communication system is provided. Described method comprises the steps:

1. Assigning at least one transmit antenna of each sector to a first transmit antenna group or a second transmit antenna group, each of the first and second transmit antenna groups having at least one transmit antenna;

2. Arranging the data into a first data stream and a second data stream;

3. performing hierarchical modulation on a carrier of a given frequency to obtain a first signal having a first base layer and a first enhancement layer;

4. performing hierarchical modulation on the carrier to obtain a second signal having a second base layer and a second enhancement layer;

5. transmitting the first signal via each transmit antenna in the first set of transmit antennas; and

6. Transmitting the second signal via each antenna of the second set of transmit antennas. the

In said method, the step of implementing hierarchical modulation is such that the first base layer carries information for the first data stream, the first enhancement layer carries information for the second data stream, and the second base layer carries information for the second data stream information, and the second enhancement layer carries the information of the first data stream. the

In one embodiment, a cellular communication system has a radio network controller and multiple sectors. Each sector has at least one transmit antenna. The radio network controller is configured to:

1. Assign at least one transmit antenna of each sector in the plurality of sectors to a first transmit antenna group or a second transmit antenna group, each antenna group of the first and second transmit antenna groups both include at least one transmitting antenna;

2. Arranging the data into a first data stream and a second data stream;

3. causing a hierarchical modulation of a carrier of a given frequency to obtain a first signal having a first base layer and a first enhancement layer (e.g., sending a command to implement such modulation to an appropriate sector);

4. Causing hierarchical modulation of said carrier to obtain a second signal having a second base layer and a second enhancement layer (e.g., sending a command to implement such modulation to an appropriate sector);

5. causing the first signal to be transmitted by each transmit antenna in the first set of transmit antennas (e.g., sending a command to effect such transmission to an appropriate sector); and

6. Causing said second signal to be transmitted via each transmit antenna in the second set of transmit antennas (e.g., sending a command to effect such transmission to an appropriate sector);

In the system, the first base layer carries information for a first data stream, the first enhancement layer carries information for a second data stream, the second base layer carries information for a second data stream, and the second enhancement layer Carries information of the first data stream. the

In one embodiment, a machine-readable medium stores instructions for at least one processor of a radio network controller of a cellular communication system. The cellular communication system includes a plurality of sectors, each sector having at least one transmit antenna. When executed by the at least one processor, the instructions configure the radio network controller to:

1. Assign at least one transmit antenna of each sector to the first transmit antenna group or the second transmit antenna group, each transmit antenna group including at least one transmit antenna;

2. Arranging the data into a first data stream and a second data stream;

3. 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;

4. causing the carrier to be hierarchically modulated to obtain a second signal having a second base layer and a second enhancement layer;

5. causing transmission of the first signal via each transmit antenna in the first set of transmit antennas; and

6. Causing transmission of the second signal via each transmit antenna of the second set of transmit antennas. the

In the described embodiment, the first base layer carries the information of the first data stream, the first enhancement layer carries the information of the second data stream, the second base layer carries the information of the second data stream, and the second enhancement layer The layer carries information of the first data stream. the

In one embodiment, a method is provided for transmitting data for a plurality of sectors in a cellular communication system, wherein each of the sectors has at least one transmit antenna. Described method comprises the steps:

1. Arrange data into multiple data streams;

2. Modulating a carrier of a given frequency with said plurality of data streams to obtain a first signal and a second signal to broadcast data from multiple sectors using multiple-input multiple-output (MTMO) space diversity techniques;

3. transmitting a first signal from each sector in a first set of sectors of said cellular communication system; and

4. Transmitting a second signal from each sector in a second set of sectors of the cellular communication system. the

In one embodiment, 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:

1. Arrange data into multiple data streams;

2. Causing said plurality of cells to modulate a carrier of a given frequency with said plurality of data streams to obtain a first signal and a second signal to broadcast from said plurality of cells using Multiple Input Multiple Output (MTMO) space diversity techniques The data;

3. causing the plurality of cells to transmit a first signal from each cell in a first set of cells of the cellular communication system; and

4. Causing the plurality of cells to transmit a second signal from each cell in a second set of cells of the cellular communication system. the

In one embodiment, 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 having at least one transmit antenna. When executed by the at least one processor, the instructions configure the radio network controller to:

1. Arrange data into multiple data streams;

2. causing the plurality of cells to modulate a carrier of a given frequency with the plurality of data streams to obtain a first signal and a second signal to broadcast signals from the plurality of sectors using multiple-input multiple-output (MTMO) space diversity techniques district data;

3. causing the plurality of cells to transmit a first signal from each cell in a first set of cells of the cellular communication system; and

4. Causing the plurality of cells to transmit a second signal from each cell in a second set of cells of the cellular communication system. the

In one embodiment, a method for receiving data transmitted from a cellular communication system is provided. The method includes receiving a first signal at a first antenna during one or more first time periods. The first signal is carried on a first frequency and includes 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 a second signal at a second antenna during the one or more first time periods. The second signal is also carried on the first frequency. The second signal includes a first data stream transmitted through the third physical channel and a second data stream transmitted through the fourth physical channel. The method also includes estimating first, second, third and fourth physical channels to obtain first, second, third and fourth channel estimates. The method also includes separating first and second data streams from at least one of a first signal and a second signal using the channel estimate. the

In one embodiment, a wireless user equipment device for communicating with a base transceiver station of a cellular communication system includes first and second antennas, a receiver coupled to the antennas, a memory storing program code, and a coupled to the processor of the receiver and the memory. The receiver is configured to receive a first signal at the first antenna during one or more first time periods. The first signal is carried on a first frequency and includes 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, and the second data stream carries second data during the one or more first time periods. The receiver is also configured to receive a second signal at the second antenna during the one or more first time periods. The second signal is also being carried on the first frequency. The second signal includes a first data stream transmitted through the third physical channel and a second data stream transmitted through the fourth physical channel. The processor is configured to estimate first, second, third and fourth physical channels to obtain channel estimates, and to combine first and second data streams with the first and second signals using the channel estimates At least one of them is separated. the

In one embodiment, a machine-readable medium stores instructions for a processor of a wireless user equipment device in communication with a cellular communication system. The instructions, when executed by a processor, cause the wireless user equipment device to receive a first signal at a first antenna during one or more first time periods. The first signal is carried on a first frequency and includes 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, and 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 a second signal from the cellular communication system at a second antenna during the one or more first time periods. The second signal is also carried on the first frequency. The second signal includes a first data stream transmitted through the third physical channel and a second data stream transmitted through the fourth physical channel. The instructions further cause the wireless user equipment device to estimate first, second, third and fourth physical channels to obtain channel estimates, and use the channel estimates to combine the first and second data streams with the first and first At least one of the two signals is separated. the

In one embodiment, a method for receiving data transmitted by a cellular communication system is provided. The method includes receiving a first signal at a first antenna. The first signal includes 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 includes a second base layer carrying a second data stream and a second enhancement layer carrying a first data stream. The method also includes receiving a second signal at a second antenna. The second signal includes 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 separation, a first data stream from the first base layer is decoded, and a second data stream from at least one of the first enhancement layer and the second base layer is decoded. Note that the first, second, third and fourth signal components are hierarchically modulated using the same carrier frequency. the

In one embodiment, a wireless user equipment device for communicating with a base transceiver station of a radio network includes first and second receive antennas, a receiver, a memory storing program code, and coupled to the receiver and the memory processor. The receiver is configured to receive a first signal at a first antenna, and to receive a second signal at a second antenna. The first signal includes 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 a second data stream and first and second enhancement layers carrying a first data stream. The second signal includes 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 a first data stream from the first base layer after separation, and to decode a second data stream from the first enhancement layer and the second base layer. the

In one embodiment, 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 a first signal at a first antenna and a second signal at a second antenna. The first signal includes 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 a second data stream and first and second enhancement layers carrying a first data stream. The second signal includes 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 use the channel estimates to separate the first and second signal components . After detaching, the instructions cause the wireless user equipment device to decode a first data stream from the first base layer, and to decode a data stream from the first enhancement layer and/or the second base layer . the

In one embodiment, a method for operating a cellular radio network having first and second space-diverse transmit antennas in a first cell is provided. The antennas are spatially diverse in order to achieve MEMO. The method includes transmitting (eg, broadcasting, multicasting) a first data stream on a first frequency via the first antenna to a plurality of user equipment devices in communication with the network. The method also includes transmitting, via the second antenna, a second data stream on the first frequency to a plurality of user equipment devices. At least some of the user equipment devices have multiple space-diverse receive antennas. In this way, the use of multiple transmit and multiple receive antennas can achieve increased spectral efficiency of transmissions. the

These and other embodiments and aspects of the invention can be better understood with reference to the following description, drawings, and appended claims. the

Description of drawings

1 is a high-level block diagram showing a cellular radio network using multiple-input multiple-output (MIMO) technology to transmit to user equipment devices according to one 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 according to one embodiment of the present invention;

3 is a high-level block diagram showing selected components of the user equipment device of FIG. 1 according to one embodiment of the present invention;

4 is a high-level block diagram showing another cellular radio network for transmission to user equipment devices using MIMO and time division multiplexing/permutation according to one embodiment of the present invention;

Figure 5 is a diagram illustrating time division multiplexing/permutation in the network of Figure 4 according to one embodiment of the present invention;

6 is a high-level block diagram showing another cellular radio network using MIMO and hierarchical modulation for transmission to user equipment devices according to an embodiment of the present invention; and

Figure 7 is a diagram illustrating time division multiplexing/permutation in the network of Figure 6 according to one embodiment of the present invention. the

Detailed ways

In this document, the words "embodiment", "modification" and similar expressions are used to refer to a specific device, process or article, and do not necessarily refer to the same device, process or article. Therefore, "one embodiment" (or similar expressions) used in one place or context may refer to a specific device, process or product; the same or similar expressions in different places may refer to different devices, processes or products. The expression "alternative embodiment" and similar phrases are used to indicate one of several different possible embodiments. The number of possible embodiments is not necessarily limited to two or any other number. the

The word "exemplary" is used herein to mean "serving as an example, instance, or understanding." Any embodiment set forth herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. All the embodiments described in this specification are provided to those skilled in the art in order to make or use exemplary embodiments of the present invention, and they are not limited to the scope of legal protection of the present invention, which is determined by the claims books and their equivalents. the

A "group" means an item or items. Thus, a transmit antenna group may include one transmit antenna or multiple transmit antennas. the

Base Transceiver Stations (BTSs) and Base Station Controllers (BSC) are part of a network called a "Radio Network", "RN", "Access Network" or "AN". A base station controller may also be referred to as a radio network controller or "RNC". The radio network may be a UTRAN or UMTS terrestrial radio access network. The radio network can transport data packets between a plurality of user equipment devices. The radio network may be further connected to additional networks other than the radio network, such as a corporate intranet, the Internet, or a conventional public switched telephone network ("PSTN"), and may be connected between each user equipment device and the external network. transfer data packets. the

A "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. Therefore, the several transmitters send out the same signal. As explained in more detail below, single frequency networks can also be configured to transmit multiple data streams on the same frequency, each data stream being transmitted from a different set of transmitters in the network. the

If the transmit power budget is the same, multiple-input multiple-output (MIMO) techniques can enable improvements in spectral efficiency for wireless communications. MIMO uses multiple space-diverse transmit antennas at the transmitting entity and multiple space-diverse antennas at the receiver. Considering the basic example of two transmit antennas NT _,1 and _NT,2 and two receive antennas NR _,1 and _NR,2 , there are four physical transmission channels: between _NT,1 and _NR,1 between CH _1,1 , _NT,1 and _NR, 2 CH _1,2 , NT _,2 and _NR,1 between CH _2,1 , NT _,2 and _NR,2 between _CH2,2 . (The symbol CH _i,j corresponds to the channel between transmit antenna _NT,i and receive antenna _NR,j .) Each of these channels is affected by several channel conditions, e.g., delay, interference, noise, multiple Path/Fade, Dispersion and Distortion. The combined effect of these conditions is usually not the same for each of these channels due to the spatial diversity of the receive and transmit antennas.

In this document, the channel coefficients corresponding to the channel CH _i,j are referred to as h _i,j . The channel matrix H representing all channels between _NT transmit antennas and _NR receive antennas can be defined as follows:

$\mathrm{<span\; class="notranslate">\; h</span>}<span\; class="notranslate">\; =</span>\left[\begin{array}{cccccc}{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="h"\; filenames="S2006800286820E00031.png,S2006800286820E00051.png"\; state="\{\{state\}\}">h</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1,1</span>}}& {\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="h"\; filenames="S2006800286820E00031.png,S2006800286820E00051.png"\; state="\{\{state\}\}">h</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1,2</span>}}& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& {\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="h"\; filenames="S2006800286820E00031.png,S2006800286820E00051.png"\; state="\{\{state\}\}">h</figure-callout></span>}}_{{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}\\ {\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 1</span>}}& {\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; 2,2</span>}}& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& {\mathrm{<span\; class="notranslate">\; h</span>}}_{{\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}\\ <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>\\ <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>\\ <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>\\ {\mathrm{<span\; class="notranslate">\; h</span>}}_{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}& {\mathrm{<span\; class="notranslate">\; h</span>}}_{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; 2</span>}}}& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& {\mathrm{<span\; class="notranslate">\; h</span>}}_{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; R</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}\end{array}\right]$

The channel coefficients _hi,j may be estimated to provide an estimate of the channel matrix H. Note that each coefficient _hi,j is not necessarily a simple multiplicative coefficient, but may include all factors affecting the associated channel.

Consider the simple case of two transmit antennas and two receive antennas (that is, _NT = 2 and _NR = 2), where the first transmit stream TS ₁ (at a given frequency F) starts from _NT,1 transmits and the second stream TS ₂ transmits from _NT,2 . On the receiver side, a first received stream RS ₁ is received at NR _,1 and a second received stream RS _,2 is received at _NR,2 . The two receive streams can be represented as follows:

RS ₁ =TS ₁ *h _1,1 +TS ₂ *h _2,1 , and

RS ₂ =TS ₁ *h _1,2 +TS ₂ *h _2,2 .

Owing to having estimates of the channel coefficients h _1,2 , h _1,2 , h _2,1 and h _2,2 the two transmit streams TS ₁ and TS ₂ can be separated at the receiver. Linear algebra techniques similarly provide a method for separating multiple streams for a larger number of transmit antennas, receive antennas and data streams. This is explained in more detail in the literature, including, for example, commonly assigned U.S. Patent Application Serial No. 11/009,200, entitled "Data Transmission With Spatial Spreading in a Mimo Communication System," Ser. No. 2005/0157805 document. See also commonly assigned U.S. Patent Application Serial No. 11/008,865, commonly assigned U.S. Patent Application entitled "Spatial Spreading in a Multi-Antenna Communication System," Document No. 11/020,888; and Commonly assigned US Patent Application Serial No. 11/020,888, entitled "Pilot Transmission and Channel Estimation for MISO and MIMO Receivers in a Multi-Antenna System," File No. 2005/0195763.

In the above discussion, it was assumed that each transmission stream is broadcast from a single antenna. It is also possible to broadcast a stream from multiple transmit antennas. In the latter case, we can treat each channel coefficient hi _,j as the coefficient of the transmission channel from the i-th group of antennas transmitting the stream TS _i to the receiving antenna (or group of receiving antennas) j. The analysis of the latter case is similar to the analysis of the case of one transmit stream per transmit antenna.

Open MEMO technology can be used as an additional option to increase the spectral efficiency of cellular SFN broadcast and multicast. Since MIMO uses multiple transmit antennas, one way to use MIMO is to transmit multiple streams from multiple antennas at the same site or sector ("cell"). the

In broadcast-targeted SFN deployments, the received signal-to-noise ratio (SNR) at the UE can be very high; for a macrocell link budget with an inter-site distance of 2800 m, the SNR is typically higher than 14 dB for 95% of users. Some system simulations show that the SFN spectral efficiency of E-MBMS is 1.2bps/Hz for 95% coverage in 1×1 deployment. Such a high SNR may enable the use of open-loop (no feedback) MIMO as an additional option for E-MBMS if there are multiple transmit and receive antennas. the

We will use the following symbols in the following discussion:

S = number of transmit streams (Tx)

N = number of cells (sectors)

N _T = number of transmit antennas per cell; and

_NR = number of receive (Rx) antennas per cell

At first, let us assume

S=min(N×N _T , _NR )>1

FIG. 1 shows a cellular single frequency radio network 105 comprising a radio network controller 110 and cells 120 and 130 . Each of these cells has a base station and two Tx antennas: cell 120 has BTS 121 and transmit antennas 122A and 122B, and cell 130 has BTS 131 and transmit antennas 132A and 132B. UE 140 has two Rx antennas 142A and 142B. Therefore, S=min(N×N _T , _NR )=min(2×2, 2)=2>1. A specific open-circuit MIMO variant of the described embodiment is to use a common periodic or pseudo-random antenna permutation (PRAP) scheme, where S streams with the same modulation and code set (MCS) combination are transmitted from each cell. Note that this makes the scheme similar to a variant of Horizontal Bell Labs Hierarchical Space-Time Code (H-BLAST). At some given time, radio network 105 may transmit a first transmission stream 151 from antennas 122A and 132A, and simultaneously transmit a second transmission stream 152 from antennas 122B and 132B.

FIG. 2 illustrates selected components of an exemplary embodiment of a radio network controller 110 . As shown in Figure 2, the radio network controller 110 includes: a BTS interface 111 that enables the RNC 110 to communicate with the BTSs 120 and 130; a processor; and a storage device 113 that stores computer code instructions. Processor 112 is coupled to storage device 113 and BTS interface 111 such that processor 112 reads and executes code stored in storage device 113 to configure BTS interface 111 to cause BTSs 120 and 130 to use the procedures described in this document to Communicate with UE 140 and other UEs. the

The radio network may include additional controllers. the

FIG. 3 illustrates selected components of an exemplary embodiment of UE 140. As shown in FIG. 3, UE 140 includes receive antennas 142A and 142B, radio network transceiver (receiver and transmitter) 143, encoder/decoder block 144, user input device (e.g., keyboard) 145, display (e.g., , LED screen) 146, processor 147 and storage device 148. Radio network transceiver 143 , encoder and decoder block 144 , user input device 145 and display 146 are configured by processor 147 under control of code stored in storage device 148 . User equipment device 140 is configured to communicate with radio network 105 over a wireless communication link using a wireless cellular network protocol, such as the cellular packet transfer protocol set forth above, and to perform the processes described in this document. the

Additional UEs may communicate with the radio network 105 . the

The radio network may also include additional base transceiver stations. the

The radio network 105 may transmit to the UE 140 using Orthogonal Frequency Division Multiplexing (OFDM). In each OFDM symbol (subcarrier), each stream may be transmitted from the radio network 105 to the UE 140 on a separate antenna; additionally, the mapping of stream IDs to transmit antenna IDs is permuted in time so that The Rx SNR of each stream is approximately equal. the

Without loss of generality, let us assume a relatively simple case for this case, where:

S=N _T .

To achieve accurate channel estimation for each Tx-Rx antenna pair, the pilot subcarriers are not reused on the Tx antennas. This is different from the data subcarrier index which is reused on all Tx antennas. Therefore, the following holds true:

i≠j，  P _i ∩ P _j = φ

i≠j,

where P _i ∈ the set of pilot subcarrier indices on antenna i.

The Rx symbol for a given OFDM symbol can be written as follows:

$\mathrm{<span\; class="notranslate">\; Y</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; ij</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; V</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; K</span>}<span\; class="notranslate">\; ]</span>$

$<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; V</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; ,</span>$

where _Xi [k] = pre-IFFT Tx modulation symbols on antenna j on subcarrier k,

H _ij [k] = SFN channel frequency response on subcarrier k from cell i and antenna j,

C _j [k] = SFN channel frequency response on subcarrier k and antenna j,

Y[k] = post-FFT Rx symbol on subcarrier k, and

H _ij [k], C _j [k], Y[k]=N _R ×1 vectors.

Note that the pilots from each antenna are orthogonal in the frequency domain, we derive this relationship:

Y[k]=C _j [k]+V _j [k] k∈P _j ,

The SFN-compliant channel frequency response for each Tx antenna can be estimated using, for example, minimum mean square error (MMSE) or a low-complexity zero-forcing robust MMSE solution. the

After channel estimation, MMSE filters can be used to achieve stream separation and inter-stream interference suppression. This can be written by invoking the orthogonal projection lemma as follows:

$\mathrm{<span\; class="notranslate">\; Y</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; V</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span>$

$\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; \&CenterDot;</span>{<span\; class="notranslate">\; [</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; i</span>}}{\stackrel{{\mathrm{<span\; class="notranslate">\; N</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}^{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; \&Lambda;</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; ]</span>}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; Y</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; ,</span>$

Where Λ[k]=E{V[k]·V ^H [k]}.

After the streams are separated at the receiver, each stream can be decoded independently and then successively canceled out from the other streams. The cancellation step can be repeated until all streams are decoded. The complexity of Sequential Interference Cancellation (SIC) depends on the number of streams. the

On the receive side, the receiver (eg, UE 140) receives a first signal using a first receive antenna and receives a second signal using a second receive antenna. The first signal includes a first data stream transmitted from a first transmit antenna or a first group of transmit antennas through a first physical channel, and a second data stream transmitted from a second transmit antenna or a second group of transmit antennas through a second physical channel. data flow. Similarly, the second signal includes the first data stream transmitted through the third physical channel and the second data stream transmitted through the fourth physical channel. The four channels are estimated at the receiver using a pilot channel or at the radio network using data provided by the receiver. The receiver may then separate the first and second data streams to obtain first and second separated data streams. 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 unsuccessful, the receiver may decode again based on the partial decoding obtained during the first attempt after canceling the interference. the

The first and second data streams may be multicast or broadcast on a shared channel. the

Since open broadcast and multicast transmissions typically target worst-case receivers, continuous interference cancellation may be omitted if not all targeted UEs implement this step. the

The discussion so far illustrates an embodiment in Fig. 1 where the SFN spectral efficiency of OFDM systems is enhanced by MIMO techniques using multiple antennas at one cell (ie, S= _NT ≥ 2). Operation of the embodiment of Figure 1 is not necessarily limited to the use of OFDM, but other methods using MIMO may be used.

As mentioned in the Background section of this document, many cells (sectors) have a single transmit antenna. Adding transmit antennas to a site involves additional costs that operators would rather avoid. Therefore, in other embodiments we do not assume diversity of transmissions from a single cell. Instead, we assume:

S=min(N*N _T , _NR )>1, and

_NT = 1 (that is, one transmit antenna per cell).

In other words, we assign transmit antennas into groups and transmit different data streams from different groups, one stream per group of transmit antennas. the

At this point, the SNR may be lower than in strict SNF operation, where all cells transmit the same flow, since each flow may be transmitted from a partial subset of network cells. However, the SNR may still be high enough to take advantage of the spatial multiplexing gain. This is especially true if the number of groups/streams is small, and as a result the number of transmit antennas in each group is relatively large, providing good coverage throughout the geographic area of interest. the

In such an arrangement, problems arise for those UEs that are inside one of the cells because these UEs have a high carrier-to-interference (C/I) ratio based on a strong signal from only one cell. These UEs cannot benefit from spatial multiplexing, but may rely on other multiplexing techniques, such as time multiplexing (TDM) and frequency multiplexing. the

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. (In the described embodiment, each cell is adjacent to a BTS, but this is not always the case.) The BTSs have respective transmit antennas 421, 425, 429 and 433. The structure of the radio network controller 410 may be similar or identical to that of the radio network controller 110 . The structure of each of UE 400A/B may also be the same or similar to that of UE 140. Here, however, the radio network 405 and UE 440A/B are configured to communicate according to the methods set forth below in connection with this embodiment. the

个小区发射N_R个流。N_R个流的每一者因此对应于相关联小区组中的一组发射天线。将流映射至发射天线组是及时置换的。  In this example, S=N _R , using ordinary PRAP or code-repeated BLAST (CR-BLAST) schemes, and at any given time from

cells transmit _NR streams. Each of the _NR streams thus corresponds to a set of transmit antennas in the associated set of cells. The mapping of streams to transmit antenna groups is permutation in time.

In this case, multiple streams are time-division multiplexed on a single transmit antenna per cell. In the case of two streams, for example, half the symbols of each slot may be dedicated to one stream and the other half to the second stream. During a first time period (T1), for example, a first symbol stream is transmitted from a first set of transmit antennas (which includes transmit antennas 425 and 433 of BTS 424 and 432) and a stream of symbols is transmitted from a second set of transmit antennas (which includes BTS 420) and 428 transmit antennas 421 and 429) transmit the second symbol stream. During a subsequent time period (T2), the first stream is transmitted from the second fire group and the second stream is transmitted from the first fire group. Then, the loop is repeated, with the stream-antenna group mapping switching iteratively. This diagram is illustrated in FIG. 5, which shows the time period T1-1 to T1-N during which the radio network transmits the first stream from the first group and the second stream from the second group; similarly, the radio network The first stream from the second group and the second stream from the first group are transmitted during time periods T2-1 to T2-N. the

Those UEs that are far enough away from each transmit antenna (e.g., UE 440A) benefit from the spatial multiplexing gain gained from using MIMO. In other words, UE 440A receives two symbol streams. Meanwhile, UEs in the cell interior (eg, UE 440B) benefit from time multiplexing and high C/I. In other words, UE 440B can only receive one of the streams at a time, but the C/I ratio is relatively high with a high SNR, especially because UE 440B is close to the transmit antenna. the

After the streams are separated, each stream can be decoded independently and then successively canceled out from all other streams. The cancellation step can be repeated until all streams are decoded. The complexity of Sequential Interference Cancellation (SIC) depends on the number of streams. the

The receiver of this embodiment may receive the first signal using the first receive antenna and the second signal using the second antenna during one or more first time periods. The first signal includes: (1) a first data stream transmitted from the first transmit antenna or the first group of transmit antennas through the first physical channel; and (2) from the second transmit antenna or the second group of transmit antennas through the first The second data stream transmitted by the second physical channel. Similarly, the second signal includes the first data stream transmitted through the third physical channel and the second data stream transmitted through the fourth physical channel. The first data stream carries first data during a first time period, and the second data stream carries second data during a first time period. the

For example, the four channels are estimated at the receiver using a pilot channel. The receiver may then separate the first and second data streams to obtain first and second separated data streams. 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

If the first attempt to decode the data is unsuccessful, the receiver may decode again based on the partial decoding obtained during the first attempt after canceling interference. the

The receiver can also decode data from signals received during subsequent time periods. Thus, if the first decoding attempt is unsuccessful, the receiver may receive the first signal at the first antenna during one or more second time periods, and may receive the first signal at the first antenna during the one or more second time periods. A second signal is received at the second antenna during a time period. The receiver may separate the first and second data streams from the first and the second signals using some or part of the channel estimate to obtain a separated first data stream and a second time period Separate the second data stream. After separating the streams, the receiver may again attempt to decode the first and second data from the first and second separated data streams for the first and second time periods. the

Remember that since TDM is used, the first signal during the second period contains the second data stream transmitted over the first physical channel and the first data stream transmitted over the second physical channel, and that the second signal contains The second data stream transmitted through the third physical channel and the first data stream transmitted through the fourth physical channel. Remember also that the first data stream carries the first data during the second time period and the second data stream carries the second data during the second time period. Accordingly, the data may be transmitted in a redundant manner during the first and second time periods. the

The first and the second data streams may be multicast or broadcast on a shared channel. the

6 illustrates a single frequency radio network 605 broadcasting or multicasting to UEs 640A and 640B using hierarchical modulation (HM) and MIMO. Radio network 605 (which is similar to network 405 of FIG. 6 ) includes a radio network controller 610 and cells/BTSs 620, 624, 628 and 632. The cells each have respective transmit antennas 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 FIG. 2 . The structure of each of UE 640A/B may also be the same as or similar to that of UE 140, which is shown in FIG. 3 . The radio network and UE 640A/B are configured to communicate according to the methods set forth below in connection with the described embodiments. the

Here, as in network 405, S= _NR , using a normal PRAP or code reuse BLAST (CR-BLAST) scheme, and _NR streams are transmitted from a cell at any given time. The stream is carried by a hierarchically modulated signal.

In hierarchical modulation, a carrier is encoded with two data streams. Considering 64-QAM (Quadrature Amplitude Modulation), the data is mapped so that 64-QAM contains a QPSK stream. This generates two data streams: a QPSK data stream and a 16-QAM data stream. The combined data rate of the two data streams may be the same as the data rate of the corresponding 64-QAM data stream. For a QPSK data stream, the symbols are encoded onto a carrier such that different segments in the complex signal plane (eg, Q-I plane) of the modulation constellation represent different positions of the symbol letter bits. For example, the left portion of the Q-I plane may correspond to a "1" value for the most significant bit of a symbol, while the right half of the plane may correspond to a "0" value for that bit. Similarly, the bottom half of the plane may correspond to a "1" value for the second most significant bit position, while the top half of the plane may correspond to a "0" value for that bit. Thus, symbols falling in the upper left quadrant will represent "10" in the two most significant bit positions, symbols in the upper right quadrant will represent "00" in those positions, and symbols in the lower left and lower right quadrants will represent "11" and "01" values. The extra bits corresponding to the symbols of the 16-QAM data stream are determined by the symbol position within the particular quadrant determined by the first two bits. the

Note that the QPSK data stream is more robust than the 16-QAM data stream, which means that the QPSK data stream can be decoded with lower SNR and lower C/I ratio of the signal. The spacing within the constellation can be varied to provide additional robustness to the QPSK data stream at the expense of the 16-QAM data stream. Thus, the more robust BPSK data stream has a greater coverage than the less robust 16-QAM data stream. the

In this document, the more robust layer in a hierarchically modulated signal (e.g., the BPSK stream in the 64-QAM example above) will be referred to as the base layer; a hierarchically modulated signal (e.g., the 16-QAM The less robust layers in the flow) will be called enhancement layers. the

Hierarchical modulation provides a mechanism to increase transmission capacity. The increase in capacity is traded off by reducing the coverage of the enhancement layer while at the same time improving the performance of the base layer. the

In SNF 605, the flow mapping may be permuted from the base layer to the enhancement layer in time. During the first time period T1 of FIG. 7, for example, the first data stream S1 may be transmitted from the first set of antennas on the base layer of the first hierarchically modulated signal, while at the same time may be transmitted on the enhancement layer of the second hierarchically modulated signal. transmit from the second set of antennas. During the second time period T2 of FIG. 5, the first data stream may be transmitted from the first set of antennas on the enhancement layer of the first hierarchically modulated signal, while at the same time may be on the base layer of the second hierarchically modulated signal. Transmit from the second set of antennas. Thus, when the first stream is transmitted on the base layer of a group of antennas, the second layer is transmitted on the enhancement layer of the group of antennas, and vice versa. In other words:

i = stream ID; and

n = OFDM symbol index. the

As in the TDM embodiment of FIG. 4, the data within each stream may be transmitted in a redundant manner during successive time periods. the

A receiver (e.g., one of UEs 640) may be configured to receive a first receive signal at a first receive antenna, the first receive signal comprising: (1) ) the first signal component transmitted through the first physical channel; and (2) the second signal component transmitted from the second transmit antenna (or second group of transmit antennas) through the second physical channel. The first signal component may comprise: (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 comprise: ( 1) a second base layer carrying a second data stream; and (2) a second enhancement layer carrying a first data stream. The receiver may be further configured to receive a second signal at the second antenna, the second signal comprising: a third signal component transmitted over a third physical channel; and (2) a first signal component transmitted over a fourth physical channel Four signal components. The third signal component may include: (1) a third base layer carrying a first data stream; and (2) a third enhancement layer carrying a 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

The first, second, third and fourth physical channels may be estimated to obtain channel estimates for the channels. Channel estimation may be implemented by the receiver and may be based on a pilot channel. The receiver may separate the first and second signal components after some or all channel estimates become available. After the signal is separated, the receiver may attempt to decode a first data stream from the first base layer and a second data stream from the first enhancement layer. the

The receiver may attempt to decode the second data stream from both the first enhancement layer and the second base layer. Alternatively, the receiver may estimate the quality of the first signal, and if the quality of the first signal (eg, SNR) is higher than a predetermined measure, decode the second data stream; if the quality of the first signal does not exceed the measurement, the receiver may use the channel estimate to separate the third and fourth signal components and attempt to decode the second data flow. The receiver may also estimate the quality of the second signal and attempt to decode a second data stream from the first enhancement layer if the quality of the second signal is below a predetermined threshold; if the second If the quality of the signal is not lower than 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. the

Interference cancellation (IC) techniques may be used to cancel interference from the base layer to the enhancement layer of the same signal. the

In cases where there are multiple transmit antennas at the Node-B and cell-specific content needs to be transmitted, the system can switch to space-time transmit diversity (STTD) or turn off the transmit diversity antennas. The first of the options may be simpler, without any RF implications of dynamically turning on/off the transmit diversity antennas. the

Although the steps of the various methods have been described in series in this disclosure, some of these steps may be performed by separate elements in a joint fashion or in parallel, asynchronous or synchronous fashion, in a pipelined fashion, or otherwise way to implement. There is no specific requirement that the steps listed in this specification be performed in the same order, unless explicitly stated, otherwise clear from context, or otherwise inherently required. Furthermore, not every illustrated step or communication is required in every embodiment in accordance with the invention, and certain steps or communications not specifically illustrated may be required in certain embodiments in accordance with the invention. the

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. the

Those skilled in the art should further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or a combination of both. To clearly show this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been summarized above in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention. the

The various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein may be constructed or implemented by a general purpose processor, digital signal processor (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic circuits, discrete hardware components, or any combination thereof designed to implement the functions shown above. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or configuration machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a combination of multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration . the

The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be directly implemented in hardware, in software modules executed by a processor, or in a combination of both. Software modules can 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. In the alternative, the storage medium may be an integral part of the processor. The processor and storage medium may reside in an ASIC. Instead, the ASIC may reside in a user equipment device. Alternatively, the processor and storage medium may reside as discrete components in the user equipment device. the

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to the described embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. the

Claims (19)

CLAIMS 1. A method of transmitting data from a plurality of sectors in a cellular communication system, the method comprising: assigning at least one transmit antenna from each of the plurality of sectors to one of L transmit antenna groups, L being an integer greater than 1, each of the L transmit antenna groups a transmit antenna group comprising at least one transmit antenna of said cellular communication system; Segmenting the data into L data streams; For at least one first period, assigning each of the L data streams to a different one of the L transmit antenna groups, thereby resulting in a first allocation of data streams among the transmit antenna groups ; For each of the L transmit antenna groups, during the at least one first period, using the a data stream to modulate a carrier wave at a first frequency; and During the at least one first period, the carrier is transmitted to a plurality of receivers through the transmit antennas of the L transmit antenna groups such that the transmit antennas of each of the transmit antenna groups are at the at least one transmitting said data streams assigned to said each transmit antenna group for said at least one first period during a first period; For at least one second period, assigning each of the data streams to a different transmit antenna group among the L transmit antenna groups, thereby generating a second allocation of the data streams among the transmit antenna groups, the second the distribution is not the same as said first distribution; For each of the L transmit antenna groups, during the at least one second period, using the a data stream to modulate the carrier; and During the at least one second period, the carrier is transmitted to a plurality of receivers through the transmit antennas of the L transmit antenna groups such that the transmit antennas of each transmit antenna group are at the at least one The data streams assigned to the each transmit antenna group for the at least one second period are transmitted during a second period. 2. The method of claim 1, wherein: L is equal to 2; The at least one first period includes a plurality of first periods; the at least one second period includes a plurality of second periods; and The first period of the plurality of first periods is interleaved with the second period of the plurality of second periods during a first duration. 3. An apparatus for transmitting data from a plurality of sectors in a cellular communication system, the apparatus comprising: means for assigning at least one transmit antenna from each of the plurality of sectors to one of L transmit antenna groups, L being an integer greater than 1, the L transmit antennas each transmit antenna group in the group includes at least one transmit antenna of the cellular communication system; means for segmenting data into L data streams; For at least one first period, assign each data stream in the L data streams to a different transmit antenna group in the L transmit antenna groups, thereby generating the first data stream in the transmit antenna group sub-distributed device; For each of the L transmit antenna groups, during the at least one first period, using the means for modulating a carrier wave of a first frequency by said data stream; and for transmitting the carrier wave to a plurality of receivers through the transmit antennas of the L transmit antenna groups during the at least one first period, such that the transmit antennas of each transmit antenna group are in the means for transmitting said data streams assigned to said each transmit antenna group for said at least one first period during at least one first period; Means for assigning each of the data streams to a different one of the L transmit antenna groups for at least one second period, thereby generating a second distribution of the data streams among the transmit antenna groups , the second allocation is different from the first allocation; For each of the L transmit antenna groups, during the at least one second period, using the at least one second period assigned to the each transmit antenna group means for modulating said carrier wave by said data stream; and for transmitting the carrier wave to a plurality of receivers through the transmit antennas of the L transmit antenna groups during the at least one second period, such that the transmit antennas of each transmit antenna group are in the means for transmitting said data streams assigned to said each transmit antenna group for said at least one second period during at least one second period. 4. A method of transmitting data from a plurality of sectors in a cellular communication system, the method comprising: assigning at least one transmit antenna for each sector of the plurality of sectors to a first set of transmit antennas or a second set of transmit antennas, each of the first and second sets of transmit antennas comprising at least one transmitting antenna; arranging the data into a first data stream and a second data stream; performing hierarchical modulation on a carrier of a given frequency to obtain a first signal having a first base layer and a first enhancement layer; performing hierarchical modulation on the carrier to obtain a second signal having a second base layer and a second enhancement layer; transmitting the first signal via each transmit antenna in the first set of transmit antennas; and transmitting the second signal via each antenna in the second set of transmit antennas; wherein the step of implementing said hierarchical modulation is such that said first base layer carries information of said first data stream, said first enhancement layer carries information of said second data stream, and said second base layer information of the second data stream is carried, and the second enhancement layer carries information of the first data stream. 5. The method of claim 4, wherein transmitting the first signal comprises broadcasting or multicasting. 6. An apparatus for transmitting data from a plurality of sectors in a cellular communication system, the apparatus comprising: means for assigning the at least one transmit antenna of each of the plurality of sectors to a first set of transmit antennas or a second set of transmit antennas, the first and second sets of transmit antennas Each antenna group of includes at least one transmit antenna; means for arranging data into a first data stream and a second data stream; means for 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; means for causing the carrier to be hierarchically modulated to obtain a second signal having a second base layer and a second enhancement layer; means for causing the first signal to be transmitted via each transmit antenna in the first set of transmit antennas; and means for causing the second signal to be transmitted via each transmit antenna in the second set of transmit antennas; Wherein the first base layer carries information of the first data stream, the first enhancement layer carries information of the second data stream, and the second base layer carries information of the second data stream information, and the second enhancement layer carries information of the first data stream. 7. A method of receiving data transmitted from a cellular communication system, the method comprising: receiving a first signal at a first antenna during one or more first time periods, the first signal carried on a first frequency, the first signal comprising a first data stream transmitted over a first physical channel and a second data stream transmitted over a second physical channel, the first data stream comprising first data during the one or more first time periods, the second data stream during the one or more first time periods Including second data during a time period; A second signal is received at a second antenna during said one or more first time periods, said second signal being carried on said first frequency, said second signal comprising a signal transmitted over a third physical channel the first data stream and the second data stream transmitted over a fourth physical channel; estimating the first physical channel to obtain one or more first channel estimates; estimating the second physical channel to obtain one or more second channel estimates; estimating the third physical channel to obtain one or more third channel estimates; estimating the fourth physical channel to obtain one or more fourth channel estimates; and associating said first and second data streams with at least one of said first signal and said second signal using at least some of said one or more first, second, third and fourth channel estimates separating, thereby generating a first separated data stream and a second separated data stream of the one or more first time periods. 8. The method of claim 7, further comprising: A first attempt is made to decode the first and the second data from the first and second separate data streams of the one or more first time periods. 9. The method of claim 8, wherein if the first attempt at decoding is unsuccessful, the method further comprises: The first signal is received at the first antenna during one or more second time periods, the first signal comprising the second data stream transmitted over the first physical channel and the second data stream transmitted over the first physical channel The first data stream transmitted by two physical channels, the first data stream contains the first data during the one or more second time periods, and the second data stream is during the one or more containing said second data during a second time period; The second signal is received at the second antenna during the one or more second time periods, the second signal comprising the second data stream transmitted over the third physical channel and the second data stream transmitted over the The first data stream transmitted by the fourth physical channel; associating said first and second data streams with at least one of said first signal and said second signal using at least some of said one or more first, second, third and fourth channel estimates separating, thereby generating a first separate data stream and a second separate data stream of the one or more second time periods; and A second attempt is made to decode the first and the second data from the first and second split data streams of the one or more first and second time periods. 10. The method of claim 7, wherein the step of receiving the first signal at the first antenna comprises receiving on a shared channel. 11. The method of claim 7, wherein the step of receiving the first signal at the first antenna comprises receiving a broadcast or multicast transmission. 12. An apparatus for receiving data transmitted from a cellular communication system, the apparatus comprising: means for receiving a first signal at a first antenna during one or more first time periods, the first signal carried on a first frequency, the first signal comprising a signal transmitted over a first physical channel A first data stream and a second data stream transmitted over a second physical channel, the first data stream comprising first data during the one or more first time periods, the second data stream during the one or more first time periods the second data is included during one or more first time periods; means for receiving a second signal at a second antenna during said one or more first time periods, said second signal being carried on said first frequency, said second signal comprising said first data stream transmitted over a physical channel and said second data stream transmitted over a fourth physical channel; means for estimating said first physical channel to obtain one or more first channel estimates; means for estimating said second physical channel to obtain one or more second channel estimates; means for estimating said third physical channel to obtain one or more third channel estimates; means for estimating the fourth physical channel to obtain one or more fourth channel estimates; and for combining said first and second data streams with at least one of said first signal and said second signal using at least some of said one or more first, second, third and fourth channel estimates means for separating one from another to generate a first separate data stream and a second separate stream of the one or more first time periods. 13. The apparatus of claim 12, further comprising a first attempt to decode the first and second separate data streams from the one or more first time periods means for describing the second data. 14. The device of claim 12, further comprising: means for receiving said first signal at said first antenna during one or more second time periods, said first signal comprising said second data stream transmitted over said first physical channel and The first data stream transmitted over the second physical channel, the first data stream containing the first data during the one or more second time periods, the second data stream during the containing said second data during one or more second time periods; means for receiving said second signal at said second antenna during said one or more second time periods, said second signal comprising said second data transmitted over said third physical channel stream and said first data stream transmitted over said fourth physical channel; for combining said first and second data streams with at least one of said first signal and said second signal using at least some of said one or more first, second, third and fourth channel estimates means for one to separate, thereby generating a first split data stream and a second split data stream for said one or more second time periods; and means for a second attempt to decode said first and said second data from said first and second split data streams of said one or more first and second time periods. 15. A method of receiving data transmitted from a cellular communication system, the method comprising: A first signal is received at a first antenna, the first signal comprising a first signal component transmitted over a first physical channel and a second signal component transmitted over a second physical channel, the first signal component comprising carrying a first A first base layer carrying a second data stream and a first enhancement layer carrying a second data stream, the second signal component comprising a second base layer carrying the second data stream and carrying the first data stream The second enhancement layer of ; A second signal is received at the second antenna, the second signal comprising a third signal component transmitted over a third physical channel and a fourth signal component transmitted over a fourth physical channel, the third signal component comprising carrying the a third base layer carrying the first data stream and a third enhancement layer carrying the second data stream, the fourth signal component comprising a fourth base layer carrying the second data stream and carrying the a fourth enhancement layer of the first data stream; estimating the first, second, third and fourth physical channels to obtain one or more channel estimates; separating the first and second signal components using the one or more channel estimates; decoding said first data stream from said first base layer after said separating step; and after said separating step, decoding said second data stream from at least one layer selected from said first enhancement layer and said second base layer; Wherein the first, second, third and fourth signal components are hierarchically modulated using the same carrier frequency. 16. The method of claim 15, wherein the step of decoding the second data stream comprises decoding the second data stream from both the first enhancement layer and the second base layer. 17. The method of claim 15, wherein the step of receiving at the first antenna includes receiving on a shared channel. 18. The method of claim 15, wherein the step of receiving at the first antenna comprises receiving a broadcast or a multicast. 19. An apparatus for receiving data transmitted from a cellular communication system, the apparatus comprising: Means for receiving at a first antenna a first signal comprising a first signal component transmitted via a first physical channel and a second signal component transmitted via a second physical channel, the first signal component comprising a first base layer carrying a first data stream and a first enhancement layer carrying a second data stream, the second signal component comprising a second base layer carrying the second data stream and carrying the the second enhancement layer of the first data stream; Means for receiving at a second antenna a second signal comprising a third signal component transmitted via a third physical channel and a fourth signal component transmitted via a fourth physical channel, the third signal component comprising a third base layer carrying the first data stream and a third enhancement layer carrying the second data stream, the fourth signal component comprising a fourth base layer carrying the second data stream and carrying a fourth enhancement layer of said first data stream; means for estimating said first, second, third and fourth physical channels to obtain one or more channel estimates; means for separating the first and second signal components using the one or more channel estimates; means for decoding said first data stream from said first base layer after said separating step; and means for decoding said second data stream from at least one layer selected from said first enhancement layer and said second base layer after said separating step; and Means for hierarchically modulating said first, second, third and fourth signal components using the same carrier frequency.

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