Apparatus and method for allocating user in a multiple antenna mobile communication system supporting multi-user diversity

• US 7,532,599 B2
• Filed: 03/14/2006
• Issued: 05/12/2009
• Est. Priority Date: 03/14/2005
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd., Yonsei University
• Original Assignee: Samsung Electronics Co. Ltd., Yonsei University
• Inventors: Ham, Jae-Sang, Kim, Kyeong-Yeon, Shim, Sei-Joon, Kim, Eung-Sun, Lee, Chung-Yong, Lee, Jong-Hyeuk
• Primary Examiner(s): Corsaro; Nick
• Assistant Examiner(s): Chambers; Tangela T.
• Application Number:
  US11/374,735
• Publication Number:
  US 20060203777A1
• Time in Patent Office: 1,155 Days
• Field of Search: 370/334
• US Class Current: 370/334
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0656 Cyclotomic systems, e.g. Bell Labs Layered Space-Time [BLAST]
• CPC Class Codes: H04L 1/0675 characterised by the signaling

Abstract

A user allocating apparatus and method in a multiple antenna mobile communication system supporting multi-user diversity is provided. Each user calculates effective Signal-to-Interference Noise Ratios (SINRs) and bit loading over every possible detection order and selects a detection order maximizing the number of channels with a minimum product of the minimum symbol distance of a modulation scheme and an effective SINR, thereby minimizing an average error probability. A base station receives detection orders from users and selects a user with a maximum detection order value. The base station then transmits data to the selected user using modulation schemes determined by the user for the transmit antennas.

Claims

1. A method of allocating a terminal in a spatial multiplexing multi-input multi-output (SM-MIMO) system, the method comprising the steps of:

calculating, by each of a plurality of terminals, an effective signal-to-interference noise ratio (SINR) of each of a plurality of channels over each of a plurality of possible detection orders;

selecting, by each of the terminals, a detection order that minimizes a highest of error probabilities of the channels from among the detection orders, wherein each of the error probabilities is based on a product of a minimum symbol distance of a modulation scheme to be used in one of the channels and the effective SINR of the one of the channels;

transmitting, by each of the terminals, to a base station, the selected detection order and modulation schemes to be used in the channels in accordance with the selected detection order;

selecting, by the base station, a terminal with a lowest average of the error probabilities from among the terminals using detection orders received from the terminals; and

setting, by the base station, the modulation schemes to be used in the channels, according to the detection order corresponding to the selected terminal,

wherein the detection order selecting step comprises selecting the detection order by

$\underset{i<br><br>\left(\mathrm{detection}<br><br><br><br>\mathrm{order}\right)}{\max }<br><br>\left(\underset{k<br><br>\left(\mathrm{Tx}<br><br><br><br>\mathrm{antenna}\right)}{\min }<br><br>\frac{g_{M_{\mathrm{ik}}}<br><br>{\mathrm{\gamma <br><br>}}_{\mathrm{ik}}}{r_i}\right)$

where i is the index of the detection order, k is the index of a transmit antenna, g_M is a constant being the minimum symbol distance of the modulation scheme, γ

is a signal-to-interference ratio (SIR) of the one of the channels, and r is a number of the channels with non-zero bits.

2. The method of claim 1, wherein the terminal selecting step comprises selecting the terminal by

$\underset{u\; <li></li>\left(\mathrm{users}\right)}{\max }<br><br>\left(\underset{i<br><br>\left(\mathrm{detection}<br><br><br><br>\mathrm{order}\right)}{\max }<br><br>\left(\underset{k<br><br>\left(\mathrm{Tx}<br><br><br><br>\mathrm{antenna}\right)}{\min }<br><br>\frac{g_{M_{\mathrm{ik}}}<br><br>{\mathrm{\gamma <br><br>}}_{\mathrm{ik}}}{r_i}\right)\right)$

where u is the index of a user, where i is the index of the detection order, k is the index of a transmit antenna, g_M is the constant being the minimum symbol distance of the modulation scheme, γ

is the SIR of the one of the channels, and r is the number of the channels with non-zero bits.

3. A method of selecting a terminal and transmitting data to the selected terminal in a base station in a spatial multiplexing multi-input multi-output (SM-MIMO) system using equal power and adaptive rate for a plurality of transmit antennas, the method comprising the steps of:

receiving from each of a plurality of terminals a detection order and modulation schemes to be used in a plurality of channels in accordance with the detection order, wherein the detection order indicates a detection order that minimizes a highest of error probabilities of the channels from among a plurality of possible detection orders, and each of the error probabilities is based on a product of a minimum symbol distance of a modulation scheme to be used in one of the channels and the effective SINR of the one of the channels;

selecting a terminal with a lowest average of the error probabilities from among the terminals using detection orders received from the terminals;

setting the modulation schemes to be used in the channels according to the detection order corresponding to the selected terminal; and

transmitting data using the modulation schemes to the selected terminal,

wherein the terminal selecting step comprises selecting the terminal by

$\underset{u<br><br>\left(\mathrm{user}<br><br><br><br>\mathrm{\tau <br><br>}\right)}{\max }<br><br>\left(\underset{i<br><br>\left(\mathrm{detection}<br><br><br><br>\mathrm{order}\right)}{\max }<br><br>\left(\underset{k<br><br>\left(\mathrm{Tx}<br><br><br><br>\mathrm{antenna}\right)}{\min }<br><br>\frac{g_{M_{\mathrm{ik}}}<br><br>{\mathrm{\gamma <br><br>}}_{\mathrm{ik}}}{r_i}\right)\right)$

where u is the index of a user, where i is the index of the detection order, k is the index of a transmit antenna. G_M is a constant being the minimum symbol distance of the modulation scheme, γ

is a signal-to-interference ratio (SIR) of the one of the channels, and r is a number of the channels with non-zero bits.

4. The method of claim 3, wherein the detection order selecting step comprises selecting the detection order by

$\underset{u\; <li></li>\left(\mathrm{user}<br><br><br><br>\mathrm{\tau <br><br>}\right)}{\max }<br><br>\left(\underset{i<br><br>\left(\mathrm{detection}<br><br><br><br>\mathrm{order}\right)}{\max }<br><br>\left(\underset{k<br><br>\left(\mathrm{Tx}<br><br><br><br>\mathrm{antenna}\right)}{\min }<br><br>\frac{g_{M_{\mathrm{ik}}}<br><br>{\mathrm{\gamma <br><br>}}_{\mathrm{ik}}}{r_i}\right)\right)$

where u is the index of a user, where i is the index of the detection order, k is the index of a transmit antenna, g_M is the constant being the minimum symbol distance of the modulation scheme, γ

is the SIR of the one of the channels, and r is the number of the channels with non-zero bits.

5. An apparatus for selecting a terminal and transmitting data to the selected terminal in a base station in a spatial multiplexing multi-input multi-output (SM-MIMO) system using equal power and adaptive rate for a plurality of transmit antennas, the apparatus comprising:

a user allocator for receiving from each of a plurality of terminals a detection order and modulation schemes to be used in a plurality of channels in accordance with the detection order, and selecting a terminal with a lowest average of the error probabilities from among the terminals using detection orders received from the terminals, wherein the detection order indicates a detection order that minimizes a highest of error probabilities of the channels from among a plurality of possible detection orders and each of the error probabilities is based on a product of a minimum symbol distance of a modulation scheme to be used in one of the channels and the effective SINR of the one of the channels; and

an adaptive modulator for setting the modulation schemes to be used in the channels according to the detection order corresponding to the selected terminal, and transmitting data using the modulation schemes to the selected terminal,

wherein the user allocator selects the terminal by

$\underset{u<br><br>\left(\mathrm{user}<br><br><br><br>\mathrm{\tau <br><br>}\right)}{\max }<br><br>\left(\underset{i<br><br>\left(\mathrm{detection}<br><br><br><br>\mathrm{order}\right)}{\max }<br><br>\left(\underset{k<br><br>\left(\mathrm{Tx}<br><br><br><br>\mathrm{antenna}\right)}{\min }<br><br>\frac{g_{M_{\mathrm{ik}}}<br><br>{\mathrm{\gamma <br><br>}}_{\mathrm{ik}}}{r_i}\right)\right)$

where u is the index of a user, where i is the index of the detection order, k is the index of a transmit antenna, g_M is a constant being the minimum symbol distance of the modulation scheme, γ

is a signal-to-interference ratio (SIR) of the one of the channels, and r is a number of the channels with non-zero bits.

6. The apparatus of claim 5, wherein the allocated user selects the detection order by

$\underset{u\; <li></li>\left(\mathrm{user}<br><br><br><br>\mathrm{\tau <br><br>}\right)}{\max }<br><br>\left(\underset{i<br><br>\left(\mathrm{detection}<br><br><br><br>\mathrm{order}\right)}{\max }<br><br>\left(\underset{k<br><br>\left(\mathrm{Tx}<br><br><br><br>\mathrm{antenna}\right)}{\min }<br><br>\frac{g_{M_{\mathrm{ik}}}<br><br>{\mathrm{\gamma <br><br>}}_{\mathrm{ik}}}{r_i}\right)\right)$

where u is the index of a user, where i is the index of the detection order, k is the index of a transmit antenna, g_M is the constant being the minimum symbol distance of the modulation scheme, γ

is the SIR of the one of the channels, and r is the number of the channels wit non-zero bits.

7. A method of transmitting a detection order in a terminal in a spatial multiplexing-multi-input multi-output (SM-MIMO) system using equal power and adaptive rate for a plurality of transmit antennas, the method comprising the steps of:

calculating an effective signal-to-interference noise ratio (SINR) of each of a plurality of channels over each of a plurality of possible detection orders;

selecting a detection order that minimizes a highest of error probabilities of the channels from among the detection orders, wherein each of the error probabilities is based on a product of a minimum symbol distance of a modulation scheme to be used in one of the channels and the effective SINR of the one of the channels; and

transmitting the selected detection order and modulation schemes to be used in the channels in accordance with the selected detection order to a base station,

wherein the detection order selecting step comprises selecting the detection order by

$\underset{i<br><br>\left(\mathrm{detection}<br><br><br><br>\mathrm{order}\right)}{\max }<br><br>\left(\underset{k<br><br>\left(\mathrm{Tx}<br><br><br><br>\mathrm{antenna}\right)}{\min }<br><br>\frac{g_{M_{\mathrm{ik}}}<br><br>{\mathrm{\gamma <br><br>}}_{\mathrm{ik}}}{r_i}\right)$

where i is the index of the detection order, k is the index of a transmit antenna, g_M is a constant being the minimum symbol distance of the modulation scheme, γ

is a signal-to-interference ratio (SIR) of the one of the channels, and r is a number of the channels with non-zero bits.

8. The SM-MIMO method of claim 7, wherein the base station selects the terminal by

$\underset{u\; <li></li>\left(\mathrm{users}\right)}{\max }<br><br>\left(\underset{i<br><br>\left(\mathrm{detection}<br><br><br><br>\mathrm{order}\right)}{\max }<br><br>\left(\underset{k<br><br>\left(\mathrm{Tx}<br><br><br><br>\mathrm{antenna}\right)}{\min }<br><br>\frac{g_{M_{\mathrm{ik}}}<br><br>{\mathrm{\gamma <br><br>}}_{\mathrm{ik}}}{r_i}\right)\right)$

where u is the index of a user, where i is the index of the detection order, k is the index of a transmit antenna, g_M is the constant being the minimum symbol distance of the modulation scheme, γ

is the SIR of the one of the channels, and r is the number of the channels with non-zero bits.

9. An apparatus for transmitting a detection order in a terminal in a spatial multiplexing-multi-input multi-output (SM-MIMO) system using equal power and adaptive rate for a plurality of transmit antennas, the apparatus comprising:

a calculator for calculating an effective signal-to-interference noise ratio (SINR) of each of a plurality of channels over each of a plurality of possible detection orders, selecting a detection order that minimizes a highest of error probabilities of the channels from among the detection orders, wherein each of the error probabilities is based on a product of a minimum symbol distance of a modulation scheme to be used in one of the channels and the effective SINR of the one of the channels, and transmitting the selected detection order and modulation schemes to be used in the channels in accordance with the selected detection order to a base station,

wherein the calculator selects the detection order by

$\underset{i<br><br>\left(\mathrm{detection}<br><br><br><br>\mathrm{order}\right)}{\max }<br><br>\left(\underset{k<br><br>\left(\mathrm{Tx}<br><br><br><br>\mathrm{antenna}\right)}{\min }<br><br>\frac{g_{M_{\mathrm{ik}}}<br><br>{\mathrm{\gamma <br><br>}}_{\mathrm{ik}}}{r_i}\right)$

where i is the index of the detection order, k is the index of a transmit antenna, g_M is a constant being the minimum symbol distance of the modulation scheme, γ

is a signal-to-interference ratio (SIR) of the one of the channels, and r is a number of the channels with non-zero bits.

10. The apparatus of claim 9, wherein the base station selects the detection order by

$\underset{u\; <li></li>\left(\mathrm{users}\right)}{\max }<br><br>\left(\underset{i<br><br>\left(\mathrm{detection}<br><br><br><br>\mathrm{order}\right)}{\max }<br><br>\left(\underset{k<br><br>\left(\mathrm{Tx}<br><br><br><br>\mathrm{antenna}\right)}{\min }<br><br>\frac{g_{M_{\mathrm{ik}}}<br><br>{\mathrm{\gamma <br><br>}}_{\mathrm{ik}}}{r_i}\right)\right)$

where u is the index of a user, where i is the index of the detection order, k is the index of a transmit antenna, g_M is the constant being the minimum symbol distance of the modulation scheme, γ

is the SIR of the one of the channels, and r is the number of the channels with non-zero bits.