Method and device in over-the-air test environment

A test chamber comprising apparatus for providing a simulated radio channel having a defined characteristic between a first device and a second device in a test environment, wherein the apparatus comprises:

• a first antenna configured to transmit signals and to provide a first radio channel between the first antenna and the second device;
• a second antenna configured to transmit signals and to provide a second radio channel between the second antenna and the second device, wherein a characteristic of the second radio channel is dissimilar to a characteristic of the first radio channel;
• a splitting circuit configured to split a signal received from the first device into at least two split signals, and to forward at least one of the at least two split signals to the first antenna and at least one of the at least two split signals to the second antenna
• a modifying circuit configured to modify a relation between the at least two split signals, thereby providing the simulated radio channel between the first device and the second device, the simulated radio channel having a characteristic that combines, in a relation corresponding to the modified relation, the characteristic of the second radio channel and the characteristic of the first radio channel;
• and
• a delay circuit comprising:
• an input configured to receive at least part of at least one of the at least two split signals;
• a delay configured to delay the received at least part of the at least one of the at least two split signals to produce a delayed output signal;
• and
• an output configured to forward the delayed output signal towards the second device,
• wherein the input is further configured to receive at least part of the forwarded delayed output signal;
• wherein the delay is further configured to delay the received at least part of the forwarded delayed output signal to produce a further delayed output signal;
• and
• wherein the output is further configured to forward the further delayed output signal towards the second device.

A method of providing a simulated radio channel with a defined characteristic between a first device and a second device in a test environment, wherein the method comprises:

• splitting a signal received from the first device into at least two split signals;
• forwarding at least one of the at least two split signals towards a first antenna and at least one of the at least two split signals towards a second antenna, the first antenna providing a first radio channel between the first antenna and the second device, and the second antenna providing a second radio channel between the second antenna and the second device, wherein a characteristic of the second radio channel is dissimilar to a characteristic of the first radio channel;
• modifying a relation between the at least two split signals to produce at least two split signals with a modified relation therebetween;
• transmitting at least one of the produced at least two split signals on a first antenna and at least one of the produced at least two split signals on a second antenna, thereby providing the simulated radio channel between the first device and the second device, the simulated radio channel having a characteristic that combines, in a relation corresponding to the modified relation, the characteristic of the second radio channel and the characteristic of the first radio channel;
• receiving, at an input of a delay circuit, at least part of the at least one of the at least split signals;
• delaying, in a delay of the delay circuit, the at least part of the at least one of the at least two split signals to produce a delayed output signal;
• forward the delayed signal to the second device via an output of the delay circuit;
• receiving, at the input, at least part of the forwarded delayed signal;
• delaying, in the delay, the received at least part of the forwarded delayed signal to produce a further delayed signal;
• and
• forwarding the further delayed signal to the second device via the output of the delay circuit.