Power allocation for superposition transmission

Patent metadata

Field	Value
Publication number	US-10193735-B2
Application number	US-201615014800-A
Country	US
Kind code	B2
Filing date	Feb 3, 2016
Priority date	Jun 9, 2015
Publication date	Jan 29, 2019
Grant date	Jan 29, 2019

Abstract

Apparatuses, systems, and methods are described for power allocation in a superposition multiple access communication system capable of using non-uniform joint constellations or super-constellations. In one method, the conditional probability of a correctly-received symbol and a normalized weighting coefficient is calculated for each receiver and then the sum of weighted efficiencies is calculated. The optimal power allocation is determined for each receiver by maximizing the sum of weighted spectral efficiencies.

First claim

What is claimed is:

1. A method of power allocation in a superposition multiple access communication system capable of using uniform and non-uniform superposition constellations (super-constellations), comprising:
for each receiver i receiving superposition multiple access transmission, calculating the conditional probability P c,i of a symbol being correctly received based on its location within a super-constellation, wherein i is an index of integers from 1 to the total number of receivers receiving superposition multiple access transmission in the super-constellation;
for the each receiver i receiving superposition multiple access transmission, calculating a normalized weighting coefficient w i ;
calculating the sum S of weighted spectral efficiencies of all of the each receiver i using the calculated conditional probability P c,i of the each receiver i and the calculated normalized weighting coefficient w i of the each receiver i; and
determining the optimal power allocation α* i for the each receiver i by maximizing the sum of weighted spectral efficiencies.

2. The method of claim 1 , wherein the superposition multiple access communication system uses Gray-mapped Non-uniform-capable Constellations (GNCs).

3. The method of claim 1 , wherein the superposition multiple access communication is Multi-User Superposition Transmission (MUST) of the Long Term Evolution (LTE) standard.

4. The method of claim 1 , wherein the conditional probability P c,i is calculated using the following equation:
P c,i =Σ k=1 M P ({circumflex over (x)} k,i =x k,i ),

where {circumflex over (x)} k,i denotes the detected symbol at the kth symbol for receiver i.

5. The method of claim 1 , wherein the normalized weighting coefficient w i is calculated based on at least one of code gain, bit robustness relying on bit location, the Modulation and Coding Scheme (MCS), and proportional fairness (PF).

6. The method of claim 1 , wherein the normalized weighting coefficient w i is calculated using the following equation:

w
i

=

c
i

⁢

log
2

⁢

M
i

+

Δ
i

⁡

(

c
i

,

s
i

)

Σ
k

⁡

(

c
k

⁢

log
2

⁢

M
k

+

Δ
k

⁡

(

c
k

,

s
k

)

)

,

where
C i is the code rate for receiver i;
S i is a flag indicating whether receiver i's bits are swapped or not; and
Δ i (C i , s i ) is a bias term to compensate at least for the effect of coding gains between inner and outer bits, and is a function of C i and S i .

7. The method of claim 1 , wherein the sum S of weighted spectral efficiencies of all receivers i is calculated using the following equation:

S
=

∑

i
=
1

K

⁢

w
i

⁢

P

c
,
i

,

where K is the total number of receivers,
the probability P c,i i of a detected symbol being correct is defined as:
P c,i =Σ k=1 M P ({circumflex over (x)} k,i =x k,i ), and

{circumflex over (x)} k,i denotes the detected symbol at the kth symbol for receiver i.

8. The method of claim 1 , wherein there is only a near receiver and a far receiver and the sum S of weighted spectral efficiencies is calculated using the following equation:
S=w F P c,F +w N P c,N ,
where W F is the weighted coefficient for the far receiver,
where W N is the weighted coefficient for the near receiver,
the probability P c , i of a detected symbol being correct is defined as:
P c,i =Σ k=1 M P ({circumflex over (x)} k,i =x k,i ), and

{circumflex over (x)} k,i denotes the d

Assignees

• Kwon Hyukjoon
• Krishnamurthy Sandeep
• Li Linbo
• Lee Jungwon
• Samsung Electronics Co Ltd

Inventors

• Kwon Hyukjoon
• Krishnamurthy Sandeep
• Li Linbo
• Lee Jungwon

Classifications

• H04W72/0473

  the resource being transmission power · CPC title

• H04L1/0009

  by adapting the channel coding (H04L1/1812 takes precedence) · CPC title

• H04L1/0001

  Systems modifying transmission characteristics according to link quality, e.g. power backoff (adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04) · CPC title

• H04L5/003

  Arrangements for allocating sub-channels of the transmission path · CPC title

• H04L1/0003

  by switching between different modulation schemes · CPC title